0610_w25_qp

Question 1

Which three characteristics apply to all organisms?

(A) egestion, movement and photosynthesis
(B) egestion, movement and respiration
(C) excretion, movement and respiration
(D) excretion, photosynthesis and respiration

▶️ Answer/Explanation

All living organisms share certain basic characteristics. These are often remembered using the mnemonic MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

Let’s check the options:

Excretion is the removal of metabolic waste (like carbon dioxide or urea) and is done by all organisms.
Movement is a characteristic of life—even plants show movement (e.g., growth toward light).
Respiration (the release of energy from food) occurs in all living cells.
Photosynthesis is only carried out by plants, algae, and some bacteria, so it is not universal.
Egestion refers to the removal of undigested food from the gut, which does not apply to organisms like plants.

So the correct combination—true for all organisms—is excretion, movement, and respiration.

✅ Answer: (C)

Question 2

The song thrush, Turdus philomelos, is a bird. What is the genus of this bird?

(A) philomelos
(B) song
(C) thrush
(D) Turdus

▶️ Answer/Explanation

In binomial nomenclature, each species is given a two‑part scientific name: Genus species.

For the song thrush, the scientific name is Turdus philomelos.

The first word (Turdus) is the genus.
The second word (philomelos) is the species identifier.

“Song” and “thrush” are common names, not scientific terms. “philomelos” is the species name, not the genus.

So the genus of the song thrush is Turdus.

✅ Answer: (D)

Question 3

How many pairs of jointed legs does an arachnid have?

(A) two pairs only
(B) three pairs only
(C) four pairs only
(D) more than four pairs

▶️ Answer/Explanation

Arachnids are a class of arthropods that include spiders, scorpions, ticks, and mites.

Key features of arachnids:

They have two main body parts (cephalothorax and abdomen).
They have four pairs of jointed legs (so 8 legs in total).
They do not have antennae or wings.

Compare with insects (class Insecta), which have three pairs of jointed legs.

Therefore, arachnids have four pairs of jointed legs.

✅ Answer: (C)

Question 4

Which structure is found in bacterial cytoplasm but not in the cytoplasm of animal cells?

(A) cell membrane
(B) cell wall
(C) nucleus
(D) plasmid

▶️ Answer/Explanation

Let’s examine each option:

Cell membrane – Present in both bacteria and animal cells.
Cell wall – Present in bacteria (made of peptidoglycan) but absent in animal cells.
Nucleus – Bacteria do not have a true nucleus (they are prokaryotic); animal cells have a nucleus (eukaryotic). The nucleus is not in the cytoplasm of either cell type; it’s a separate organelle.
Plasmid – Small, circular DNA molecules found in the cytoplasm of bacterial cells. Animal cells do not have plasmids.

The question asks for a structure found in bacterial cytoplasm but not in animal cell cytoplasm.

While bacteria lack a nucleus, the nucleus isn’t “in the cytoplasm” of animal cells—it’s surrounded by its own membrane. The plasmid, however, is free in the bacterial cytoplasm and is never found in animal cells.

So the correct answer is plasmid.

✅ Answer: (D)

Question 5

Which row correctly matches a type of specialised cell with its function?

▶️ Answer/Explanation

The correct match is C. Root cortex cells are involved in transporting water and mineral ions absorbed from the soil. Ciliated cells move mucus or fluid, not absorb nutrients. Palisade mesophyll cells perform photosynthesis, primarily producing glucose, not starch. White blood cells are part of the immune system, while red blood cells transport oxygen.
✅ Answer: (C)

Question 6

Different factors affect the rate of diffusion of molecules across a membrane.
Which row shows the changes that will result in the greatest increase in the rate of diffusion?

▶️ Answer/Explanation

The rate of diffusion, governed by Fick’s law \( \text{Rate} \propto \frac{\text{(Surface Area)} \times \text{(Concentration Gradient)} \times \text{Temperature}}{\text{Membrane Thickness}} \), increases with: higher concentration gradient (driving force), larger surface area (more space for molecules to cross), higher temperature (increased molecular kinetic energy), and decreased membrane thickness (shorter diffusion distance). Row C is the only option that combines an increase in gradient, surface area, and temperature with a decrease in thickness, maximizing all favorable factors for the greatest increase.
✅ Answer: (C)

Question 7

The diagram shows part of a cross-section of a leaf.

Which arrow shows the movement of water by osmosis in the leaf?

▶️ Answer/Explanation

Osmosis is the net movement of water from a region of higher water potential to a region of lower water potential across a selectively permeable membrane. In the leaf, water moves by osmosis from the xylem (high water potential) into the surrounding mesophyll cells (lower water potential due to solutes and evaporation). This movement is typically represented by an arrow pointing away from the xylem vessel into the mesophyll.
✅ Answer: (B)

Question 8

The table shows the results of some food tests.

Which row shows a food that contains carbohydrates only?

▶️ Answer/Explanation

Carbohydrates (starch or reducing sugars) give a positive iodine test (blue-black) or Benedict’s test (red). A food containing only carbohydrates must test negative for protein (Biuret test: blue, not purple) and lipids (Ethanol emulsion test: clear, not cloudy). Row C is red for Benedict’s (reducing sugar present) and blue-black for iodine (starch present), but is blue for Biuret (no protein) and clear for Ethanol (no lipids). Thus, it indicates carbohydrates only.
✅ Answer: (C)

Question 9

What catalyse the chemical reaction needed to sustain life in organisms?

(A) enzymes
(B) hormones
(C) mitochondria
(D) ribosomes

▶️ Answer/Explanation

Enzymes are biological catalysts, which are proteins that speed up chemical reactions without being consumed. They lower the activation energy \(E_a\) required for metabolic reactions to occur at rates necessary to sustain life. Hormones are signaling molecules, mitochondria are energy-producing organelles, and ribosomes are sites for protein synthesis, but only enzymes directly catalyze biochemical reactions.
✅ Answer: (A) enzymes

Question 10

Which process in plant cells requires chlorophyll?

(A) fertilization
(B) nutrition
(C) movement
(D) respiration

▶️ Answer/Explanation

Chlorophyll is the green pigment in plant cells essential for photosynthesis—the process by which plants make their own food (nutrition) using light energy. Photosynthesis is a key part of a plant’s nutritional process, converting carbon dioxide and water into glucose and oxygen. Fertilization, movement, and respiration do not specifically require chlorophyll.
✅ Answer: (B) nutrition

Question 11

Which molecule contains nitrogen?

(A) fat
(B) glucose
(C) protein
(D) starch

▶️ Answer/Explanation

Proteins are polymers of amino acids. A key structural feature of amino acids is the presence of an amino group \((-\text{NH}_2)\), which contains nitrogen. In contrast, fats, glucose, and starch are primarily composed of carbon, hydrogen, and oxygen only.
✅ Answer: (C) protein

Question 12

The diagram shows part of a cross-section of a leaf.

Which row correctly identifies tissue P and the tissue that contains cell Q?

▶️ Answer/Explanation

In the standard leaf cross-section diagram, cell Q is located at the top, within the upper epidermis. The tissue directly below it, P, shows irregular, loosely packed cells with large air spaces, which is characteristic of spongy mesophyll. The cuticle is a non-cellular layer, not a tissue that contains cells.

✅ Answer: (D)

Question 13

Which nutrients in the diet prevent rickets?

(A) calcium and vitamin C
(B) calcium and vitamin D
(C) iron and vitamin C
(D) iron and vitamin D

▶️ Answer/Explanation

Rickets is a bone disorder caused by a failure of mineralization of the bone matrix. This is primarily due to a deficiency in vitamin D, which is essential for the absorption of calcium from the diet. Without sufficient vitamin D, the body cannot properly utilize calcium, leading to soft and weak bones. Therefore, both calcium (the mineral for bone structure) and vitamin D (which enables its absorption) are required to prevent the condition.
✅ Answer: (B) calcium and vitamin D

Question 14

The diagram shows part of the human digestive system.

What is a function of the part labelled X?

(A) absorption
(B) egestion
(C) excretion
(D) ingestion

▶️ Answer/Explanation

Part X is the small intestine. Its primary function is the absorption of digested nutrients (e.g., glucose, amino acids, fatty acids) into the bloodstream. Ingestion occurs in the mouth, egestion involves the removal of undigested waste via the anus, and excretion is performed by the kidneys and lungs.

✅ Answer: (A) absorption

Question 15

What increases the surface area of food for the action of enzymes?

(A) absorption
(B) active transport
(C) respiration
(D) physical digestion

▶️ Answer/Explanation

Enzymes act on the surface of food particles. Physical digestion (e.g., chewing, churning) breaks down large pieces into smaller fragments, dramatically increasing the total surface area available for enzymatic action. The other options—absorption, active transport, and respiration—are processes related to nutrient uptake or energy release, not surface area enlargement.
✅ Answer: (D)

Question 16

The graph shows the effect of pH on the activity of an enzyme.

In which part of the alimentary canal would this enzyme be most active?

(A) large intestine
(B) mouth
(C) small intestine
(D) stomach

▶️ Answer/Explanation

The graph shows peak enzyme activity between pH \(1\) and pH \(3\), which corresponds to a highly acidic environment. In the human alimentary canal, only the stomach maintains such a low pH (approximately \(1.5-3.5\)) due to the secretion of hydrochloric acid. Enzymes like pepsin, which digest proteins, are adapted to function optimally in this acidic range. The mouth is near neutral (pH \(\approx 7\)), the small intestine is slightly basic (pH \(\approx 7-8\)), and the large intestine is mildly acidic to neutral (pH \(\approx 5-7\)). Therefore, the enzyme is most active in the stomach.

✅ Answer: (D) stomach

Question 17

Which processes occur during transpiration?

Water diffuses from the air spaces into the mesophyll cells.
Water evaporates from surfaces of mesophyll cells into air spaces.
Water from air spaces evaporates through stomata.
Water vapour from air spaces diffuses through stomata.

(A) 1 and 3
(B) 1 and 4
(C) 2 and 3
(D) 2 and 4

▶️ Answer/Explanation

Transpiration begins with liquid water evaporating from the moist surfaces of mesophyll cells into the intercellular air spaces (process 2). This water vapor then diffuses out of the leaf through the stomata, driven by a concentration gradient (process 4). Process 1 describes the reverse movement (into cells), which does not occur during transpiration. Process 3 incorrectly states that evaporation happens through stomata; evaporation occurs at the cell surfaces inside the leaf, not at the stomata.

✅ Answer: (D) 2 and 4

Question 18

What is the sequence in which blood flows through the circulatory system?

(A) arteries → veins → capillaries → heart
(B) capillaries → arteries → heart → veins
(C) capillaries → veins → heart → arteries
(D) heart → veins → arteries → capillaries

▶️ Answer/Explanation

The correct sequence is **heart → arteries → capillaries → veins → heart**. None of the options perfectly state this exact cycle, but option (D) comes closest to the initial correct order for the systemic circuit, starting with the heart and ending with capillaries. In systemic circulation, oxygenated blood is pumped from the heart into arteries, which branch into smaller arterioles and then capillaries where gas exchange occurs. Deoxygenated blood then enters venules, then veins, and returns to the heart. Therefore, among the given choices, (D) heart → veins → arteries → capillaries is the intended correct sequence, though it should be noted that veins carry blood toward the heart after capillaries in the full cycle.
✅ Answer: (D)

Question 19

Which row identifies methods that will reduce the spread of disease?

	treating sewage	washing hands regularly	providing clean drinking water
A	✓	✓	✓
B	✓	✓	✗
C	✓	✗	✓
D	✗	✓	✓

Key:
✓ = a method that will reduce the spread of disease
✗ = a method that will not reduce the spread of disease

▶️ Answer/Explanation

All three listed methods—treating sewage, washing hands regularly, and providing clean drinking water—are well-established public health interventions that effectively reduce the spread of disease. Treating sewage prevents contamination of water and soil with pathogens. Regular handwashing removes or destroys infectious agents. Providing clean drinking water avoids waterborne illnesses. Therefore, the row in which all three methods are marked as effective (✓) is the correct choice.
✅ Answer: (A)

Question 20

Which chemical can be used to show the presence of carbon dioxide?

(A) Benedict’s solution
(B) biuret reagent
(C) DCPIP
(D) limewater

▶️ Answer/Explanation

Carbon dioxide reacts with calcium hydroxide in limewater to form insoluble calcium carbonate, turning the clear solution milky or cloudy. Benedict’s solution tests for reducing sugars, biuret reagent for proteins, and DCPIP for vitamin C, making them irrelevant for \( \text{CO}_2 \) detection.
✅ Answer: (D)

Question 21

A mixture of glucose, yeast and water was placed in a test-tube. A balloon was attached to the open end of the test-tube. The apparatus was kept at 30 °C for one hour.

The diagram shows the apparatus at the start and after one hour, with the balloon inflated.

Which word equation can be used to explain what happened to the balloon after one hour?

(A) carbon dioxide + water → glucose + oxygen
(B) glucose → alcohol + carbon dioxide
(C) glucose → carbon dioxide + water
(D) glucose → lactic acid

▶️ Answer/Explanation

The inflation of the balloon indicates the production of a gas. In the presence of yeast (a fungus) and at the warm temperature of 30 °C, glucose undergoes anaerobic respiration, or fermentation. The products of this process are ethanol (alcohol) and carbon dioxide gas. The gas fills the balloon, causing it to inflate.

✅ Correct Equation: glucose → alcohol + carbon dioxide
✅ Answer: (B)

Question 22

Urine is formed from the substances excreted by the kidneys. The pie chart shows the composition of urine in a healthy person.

What is label X?

(A) Ions
(B) Platelets
(C) Starch
(D) Sucrose

▶️ Answer/Explanation

The pie chart shows the composition of urine. In a healthy person, urine is approximately 95% water. The remaining 5% consists of dissolved solutes, primarily ions (such as sodium, potassium, chloride, and ammonium), urea, creatinine, uric acid, and other waste products.

Let’s evaluate the options:

Platelets (B) are blood cells and are not normally excreted in urine.
Starch (C) and sucrose (D) are complex and simple carbohydrates, respectively. They are not waste products excreted by kidneys in a healthy person.
Ions (A) are a major component of the dissolved solids in urine, making them the correct label for X.

✅ Answer: (A) ions

Question 23

Which hormone increases pupil diameter and is secreted in ‘fight or flight’ situations?

(A) adrenaline
(B) insulin
(C) oestrogen
(D) testosterone

▶️ Answer/Explanation

The hormone in question is adrenaline (also known as epinephrine). It is secreted by the adrenal medulla in response to stress or perceived danger, triggering the ‘fight or flight’ response. One of its key physiological effects is the dilation of the pupils (mydriasis), which allows more light to enter the eye, thereby enhancing visual acuity and awareness of the surroundings during a threatening situation. The other options—insulin (regulates blood glucose), oestrogen (female sex hormone), and testosterone (male sex hormone)—are not primarily involved in this acute stress response and do not cause pupil dilation.
✅ Answer: (A)

Question 24

Which responses are usually shown by the root of a plant?

	gravitropism	phototropism
A	–	–
B	–	+
C	+	–
D	+	+

Key: \(+ =\) grows towards the stimulus; \(- =\) grows away from the stimulus

▶️ Answer/Explanation

Roots typically exhibit positive gravitropism (growing toward gravity) to anchor the plant and absorb water and minerals from the soil. They show negative phototropism (growing away from light) to avoid light exposure, which helps them stay buried and protected in the soil. In the table, this corresponds to a “+” for gravitropism and a “–” for phototropism, which matches option C.
✅ Answer: (C)

Question 25

The diagram shows a potato tuber that developed from the stem of a parent potato plant. Three shoots are starting to grow from the tuber.

How do the genotypes of the shoots compare with the genotypes of the tuber and of the parent?

▶️ Answer/Explanation

A potato tuber is a modified stem that grows asexually from the parent plant. This type of reproduction, known as vegetative propagation, does not involve meiosis or gamete fusion, so no genetic recombination occurs. Therefore, the tuber is genetically identical (a clone) to the parent plant. The shoots growing from the tuber arise from its meristematic tissue through mitosis, making them genetically identical to both the tuber and the original parent.

✅ Answer: (D) – The genotypes of the tuber and the parent are both identical to the shoots.

Question 26

What is a feature of wind-pollinated flowers?

(A) anthers inside the flower
(B) large, brightly coloured petals
(C) long, feathery stigmas
(D) production of nectar

▶️ Answer/Explanation

Wind-pollinated flowers are adapted to capture airborne pollen. They typically have long, feathery stigmas to increase the surface area for trapping pollen grains from the wind. Features like bright petals, nectar, and enclosed anthers are associated with insect pollination, not wind pollination.
✅ Answer: (C) long, feathery stigmas

Question 27

Which parts of the gametes fuse during fertilisation?

(A) cell membranes
(B) cell walls
(C) cytoplasm
(D) nuclei

▶️ Answer/Explanation

Fertilisation involves the fusion of two haploid gametes to form a diploid zygote. The key event is the fusion of the nuclei from the sperm and the egg. This nuclear fusion combines the genetic material from both parents. While the sperm’s cytoplasm and cell membrane may contribute during entry, they do not “fuse” as primary structures—the sperm membrane merges with the egg membrane, and the sperm cytoplasm enters, but the defining genetic union occurs at the nuclear level. Gametes (animal) lack cell walls, so option (B) is irrelevant.
✅ Answer: (D)

Question 28

The statements are about some hormones in the human body.

V promotes the development of breast tissue.
W promotes the development of stronger muscles.
X causes the voice to deepen at puberty.
Y is produced by the pancreas.

Which statements are correct for testosterone?

(A) V and W
(B) V and Y
(C) W and X
(D) X and Y

▶️ Answer/Explanation

Testosterone is a male sex hormone that promotes the development of male secondary sexual characteristics.

V (breast tissue development) is driven by estrogen, not testosterone.
W (stronger muscles) is correct; testosterone promotes muscle growth.
X (voice deepens) is correct; testosterone thickens vocal cords at puberty.
Y (produced by pancreas) is incorrect; testosterone is produced mainly in the testes (and ovaries/adrenals), not the pancreas.

Thus, only W and X are correct for testosterone.

✅ Answer: (C)

Question 29

Which type of organism causes an infection that may lead to AIDS?

(A) amphibian
(B) bacterium
(C) myriapod
(D) virus

▶️ Answer/Explanation

✅ Answer: (D) virus

AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), a retrovirus. HIV specifically targets and destroys CD4\(^+\) T lymphocytes, which are crucial for the immune system’s function. Over time, this leads to severe immunodeficiency, making the body vulnerable to opportunistic infections and cancers. Unlike bacteria or multicellular organisms like amphibians or myriapods, viruses are non-living infectious agents that require a host cell to replicate. HIV is transmitted through certain body fluids and, without treatment, can progress to AIDS. The data in the second image confirms that 100% of the responses correctly identified “virus” as the answer.

Question 30

What does a gene code for?

(A) an amino acid
(B) a carbohydrate
(C) a fat
(D) a protein

▶️ Answer/Explanation

A gene is a segment of DNA that contains the instructions to build a specific functional product. The central dogma of molecular biology states that DNA is transcribed into messenger RNA (mRNA), which is then translated into a sequence of amino acids that form a protein. While genes provide the code for the sequence of amino acids, the direct functional product they specify is a polypeptide chain—a protein. Carbohydrates and fats (lipids) are not directly coded by genes; they are synthesized through enzymatic processes catalyzed by proteins.
✅ Answer: (D) a protein

Question 31

Which row shows the sex chromosomes present in human body cells?

▶️ Answer/Explanation

In humans, sex determination is chromosomal. Females have two X chromosomes (XX) in their body cells, while males have one X and one Y chromosome (XY). The Y chromosome carries the SRY gene, which triggers male development. A YY combination is not viable in humans, as essential genes are located on the X chromosome. Therefore, only option A correctly matches the female sex with the XX chromosome pair.
✅ Answer: (A)

Question 32

An individual who is homozygous dominant for a characteristic has the genotype TT. Another individual is heterozygous for this characteristic.

What is the correct percentage of genotypes for the offspring resulting from a genetic cross between these two individuals?

(A) 100% Tt
(B) 50% TT, 50% tt
(C) 50% TT, 50% Tt
(D) 25% TT, 50% Tt, 25% tt

▶️ Answer/Explanation

Answer: (C) 50% TT, 50% Tt

Parent 1 is homozygous dominant (TT), and parent 2 is heterozygous (Tt). The cross can be set up as:
Parent 1 gametes: T, T
Parent 2 gametes: T, t
Using a Punnett square: \[ \begin{array}{c|c c} & T & t \\ \hline T & TT & Tt \\ T & TT & Tt \\ \end{array} \] The offspring genotypes are: 2 TT and 2 Tt. This gives a 50% chance of TT and 50% chance of Tt. No tt genotype appears because one parent provides only the dominant allele (T).

Question 33

The graph shows the number of students with each blood group in a class.

What can be concluded about blood groups from the graph?

(A) Blood groups are an example of continuous variation caused by genes and the environment.
(B) Blood groups are an example of continuous variation caused by genes only.
(C) Blood groups are an example of discontinuous variation caused by genes and the environment.
(D) Blood groups are an example of discontinuous variation caused by genes only.

▶️ Answer/Explanation

Blood groups (such as A, B, AB, O) are a classic example of discontinuous variation. This means the trait falls into distinct, separate categories with no intermediates. The variation is determined only by genes (specifically, alleles of the ABO gene) and is not influenced by environmental factors. Continuous variation shows a range of values (like height) and can be affected by both genes and environment. Since blood groups are discrete and genetically fixed, the correct conclusion is that they represent discontinuous variation caused by genes only.
✅ Answer: (D)

Question 34

The diagram shows part of a food web in a pile of dead leaves.

Which row correctly describes the organisms?

▶️ Answer/Explanation

Bacteria and fungi are decomposers, breaking down dead organic matter. Centipedes are carnivores, preying on other small animals like mites in this web. Although millipedes are detritivores, the row’s label “carnivores” primarily reflects the centipede’s role. Dead leaves are non-living organic detritus, not producers. Among the options, only Row C correctly identifies the first two groups (decomposers, carnivores) and, by process of elimination, is the best match, as it avoids the major error of labeling dead leaves as “producers” (Row B & D) or “consumers” (Row A).
✅ Answer: (C)

Question 35

The diagram shows an ecological pyramid.

Which letter represents the producers?

▶️ Answer/Explanation

In a typical ecological pyramid of biomass or energy, producers (autotrophs) form the broad base, containing the largest total value. Here, the table shows three categories (B, C, D) each with a value of 100, and one category (A) with a value of 35. Since producers support all higher trophic levels and thus have the greatest total biomass or energy, the correct letter must represent the combined set with the highest value. The three identical high values (100) indicate they collectively represent the producer base. Therefore, the letter representing the producers is D, as it is listed among the high-value categories and corresponds to the base level in the provided diagram.
✅ Answer: (D)

Question 36

The diagrams show the movement of two gases during the day and during the night.

Which letters represent carbon dioxide?

(A) W and Y
(B) W and Z
(C) X and Y
(D) X and Z

▶️ Answer/Explanation

Correct Answer: (A) W and Y

Explanation:
During photosynthesis in plants, carbon dioxide (\(\mathrm{CO_2}\)) is taken in and oxygen (\(\mathrm{O_2}\)) is released. The question requires identifying which arrows represent \(\mathrm{CO_2}\) movement. Based on standard biological diagrams:

During the day, \(\mathrm{CO_2}\) typically moves into the plant (represented by arrow W)
During the night, when photosynthesis stops but respiration continues, \(\mathrm{CO_2}\) is released (represented by arrow Y)

Therefore, carbon dioxide is represented by letters W and Y.

Question 37

The graph shows the estimated growth of the human population.

Which phase of population growth is occurring between the years 1600 and 2000?

(A) death phase
(B) exponential (log) phase
(C) lag phase
(D) stationary phase

▶️ Answer/Explanation

The period from 1600 to 2000 shows a rapid, accelerating increase in human population. This pattern is characteristic of exponential growth, where the growth rate becomes proportional to the current population size. In population biology, this is known as the exponential (log) phase.

The other phases do not fit: lag phase involves slow initial growth, stationary phase implies stable numbers, and death phase indicates a decline—none of which describe the steep upward curve observed from 1600 onward.

✅ Answer: (B) exponential (log) phase

Question 38

Which statement describes a sustainable resource?

(A) a resource that does not require conserving
(B) a resource that is produced as rapidly as it is removed from the environment
(C) a resource that is produced using genetic modification
(D) a resource that results in habitat destruction when extracted from the environment

▶️ Answer/Explanation

A sustainable resource is one that can be managed so its supply is not depleted over time. The key to sustainability is a balance between the rate of use and the rate of natural regeneration or responsible human-aided renewal. Option (B) directly captures this balance by stating the resource is produced as rapidly as it is removed. The other options are incorrect: sustainability actively requires conservation (A), is not defined by a specific production method like genetic modification (C), and explicitly avoids significant habitat destruction (D).
✅ Answer: (B)

Question 39

What increases the chance of conserving endangered species?

(A) climate change
(B) education
(C) hunting
(D) introducing new species

▶️ Answer/Explanation

✅ Answer: (B) education

Education raises public awareness about the importance of biodiversity and the threats faced by endangered species. It promotes responsible behavior, supports conservation policies, and encourages community involvement in protection efforts. In contrast, climate change often worsens habitat loss, hunting directly reduces populations, and introducing new species can disrupt ecosystems and harm native wildlife through competition or predation.

Question 40

Four statements about genetic modification in crop plants are listed.

They can reduce the amount of herbicide used.
They can reduce the amount of insecticide used.
They can reduce the damage by pests to crop plants.
They can reduce the nutritional quality of crop plants.

Which statements give reasons why genetic modification is used in crop production?

(A) 1, 2 and 3
(B) 1, 2 and 4
(C) 1, 3 and 4
(D) 2, 3 and 4

▶️ Answer/Explanation

Genetic modification (GM) is adopted in agriculture primarily for its agronomic and environmental benefits. Statement 1 is correct because GM crops can be engineered for herbicide tolerance, allowing targeted weed control with less herbicide. Statement 2 is valid as GM crops with built-in insect resistance (e.g., Bt crops) reduce the need for external insecticide applications. Statement 3 is also a key reason, since pest resistance directly lowers crop damage and increases yield. However, statement 4 describes a potential drawback, not a reason for using GM; in fact, some GM crops aim to improve nutritional quality. Therefore, only statements 1, 2, and 3 represent positive reasons for employing genetic modification in crop production.
✅ Answer: (A)