Topic – 1.1
Students find a small organism in a pond. They catch it and put it into a large jar of water. They see that the organism swims away from light. It lays some eggs before it is put back into the pond.
Which characteristics of living things did the students see in this organism?
A) excretion, growth and respiration
B) growth, nutrition and sensitivity
C) movement, reproduction and sensitivity
D) movement, reproduction and respiration
▶️ Answer/Explanation
Ans: C
The organism exhibits movement (swimming), reproduction (laying eggs), and sensitivity (responding to light). These are clearly observed characteristics in the scenario.
Excretion (A) and respiration (D) are not mentioned, while growth (B) is not directly observed. Thus, the correct answer is C (movement, reproduction, and sensitivity).
Topic – 1.2
Which description of a species is correct?
A) a group of organisms living at the same time
B) a group of organisms living in the same area
C) a group of organisms that can reproduce to produce fertile offspring
D) a group of organisms that have adaptive features
▶️ Answer/Explanation
Ans: C
A species is defined as a group of organisms that can interbreed and produce fertile offspring (C). This is the biological definition of a species, distinguishing it from other groups.
Option A refers to a temporal group, B describes a population, and D refers to adaptations, none of which define a species. Thus, the correct answer is C.
Topic – 1.3
The table shows the number of animals collected in a sample from a woodland and the groups to which they belong.
How many of the animals, in total, are arthropods with six or eight legs?
A) 15
B) 88
C) 90
D) 98
▶️ Answer/Explanation
Ans: C
Arthropods with six legs are insects (85 in the table), and those with eight legs are arachnids (5 in the table). The total number of arthropods with six or eight legs is:
\[ 85 \text{ (insects)} + 5 \text{ (arachnids)} = 90 \]
Thus, the correct answer is C (90).
Topic – 1.3
Some vertebrates have body hair.
Which group do these vertebrates belong to?
A) amphibian
B) bird
C) mammal
D) reptile
▶️ Answer/Explanation
Ans: C
Body hair is a defining characteristic of mammals (C), as they are the only vertebrates that possess it. Amphibians (A) have moist skin, birds (B) have feathers, and reptiles (D) have scales. Thus, the correct answer is C (Mammal).
Topic – 2.1
The diagram shows two guard cells from a leaf.
Which labelled part would also be found in sperm cells?
▶️ Answer/Explanation
Ans: A
Guard cells and sperm cells are both eukaryotic cells containing common organelles like the nucleus (A), mitochondria, and cell membrane. However, chloroplasts (B) are only in plant cells, the thick cell wall (C) is plant-specific, and stomatal pores (D) are unique to guard cells.
Since sperm cells require genetic material for reproduction, they must contain a nucleus, making A the correct answer.
Topic – 2.1
The photograph shows part of a cross-section of a root.
The root hair and the xylem are part of the same
A) cell and organism.
B) cell and tissue.
C) organ and organism.
D) tissue and organ.
▶️ Answer/Explanation
Ans: C
The root hair is a specialized cell that absorbs water and minerals, while the xylem is a vascular tissue that transports these substances. Both structures are part of the root organ, which is itself part of the entire plant organism.
Option A is incorrect because the root hair and xylem are not part of the same cell. Option B is incorrect because the xylem is a tissue, not a cell. Option D is incorrect because the root hair is not a tissue. Thus, the correct answer is C (organ and organism).
Topic – 2.2
Which formula is correct for calculations involving image size, actual size and magnification?
A) actual size = image size × magnification
B) image size = magnification × actual size
C) magnification = actual size ÷ image size
D) magnification = image size × actual size
▶️ Answer/Explanation
Ans: B
The correct formula relating image size, actual size, and magnification is:
\[ \text{Image Size} = \text{Magnification} \times \text{Actual Size} \]
Option B matches this relationship. The other options are incorrect because:
– A swaps image size and actual size, C inverts the ratio, and D incorrectly multiplies image size and actual size.
Topic – 3.1
Which statements about diffusion are correct?
- Diffusion is the net movement of particles from a higher to a lower concentration.
- Diffusion is the net movement of particles only across cell membranes.
- Diffusion requires energy from respiration.
A) 1, 2 and 3
B) 1 and 2 only
C) 1 only
D) 2 and 3 only
▶️ Answer/Explanation
Ans: C
Statement 1 is correct: Diffusion is the net movement of particles from a region of higher concentration to lower concentration.
Statement 2 is incorrect: Diffusion occurs in any medium (e.g., air, water) and is not restricted to cell membranes.
Statement 3 is incorrect: Diffusion is a passive process and does not require energy from respiration.
Since only Statement 1 is correct, the answer is C (1 only).
Topic – 3.2
What is the name of the process in which water moves through a partially permeable membrane?
A) active transport
B) evaporation
C) osmosis
D) transpiration
▶️ Answer/Explanation
Ans: C
Osmosis (C) is the correct answer because it is defined as the movement of water molecules across a partially permeable membrane from a region of lower solute concentration to higher solute concentration. This passive process does not require energy.
Active transport (A) requires energy, evaporation (B) is liquid-to-gas phase change, and transpiration (D) is water movement through plants. The question specifically describes osmosis.
Topic – 4.1
A sample of food is tested with different chemical substances.
The table shows the results.
Which nutrients does the sample of food contain?
A) protein and vitamin C
B) protein only
C) starch and reducing sugar
D) starch and vitamin C
▶️ Answer/Explanation
Ans: A
The table indicates a positive test for protein (Biuret test turns purple) and vitamin C (DCPIP turns colorless). Starch (iodine test) and reducing sugar (Benedict’s test) show negative results, ruling out options C and D. Since both protein and vitamin C are detected, the correct answer is A.
Topic – 5.1
The diagram shows an experiment on the digestion of the protein in egg albumen by protease.
The protease was taken from a human stomach.
In which test-tube will protein be digested most quickly?
▶️ Answer/Explanation
Ans: C
Protease, an enzyme from the stomach, works best in acidic conditions (pH ~2) at body temperature (37°C). Test-tube C has both these optimal conditions, ensuring the fastest digestion of egg albumen.
Test-tubes A and B lack the correct pH, while D is too cold. Thus, C is the correct answer.
Topic – 5.1
The diagram represents the shape of an enzyme molecule.
With which substrate would this enzyme most easily form an enzyme–substrate complex?
▶️ Answer/Explanation
Ans: D
Enzymes exhibit specificity, meaning they bind only to substrates with a complementary shape. The enzyme’s active site (shown in the diagram) has a distinct structure that matches substrate D.
Substrates A, B, and C do not fit the enzyme’s active site as precisely as D. The lock-and-key model explains why D forms the most stable enzyme-substrate complex.
Topic – 6.1
The diagram shows an experiment to investigate photosynthesis.
What is the most abundant gas present at the top of the tube at the end of the experiment?
A) carbon dioxide
B) methane
C) water vapour
D) oxygen
▶️ Answer/Explanation
Ans: D
During photosynthesis, plants absorb carbon dioxide and release oxygen as a byproduct. The experiment likely involves an aquatic plant (e.g., Elodea) in water, where oxygen bubbles accumulate at the tube’s top.
While water vapor (C) may be present, it condenses easily, and methane (B) is irrelevant here. Carbon dioxide (A) is consumed, not produced. Thus, the most abundant gas is oxygen (D).
Topic – 6.1
The graph shows how the percentage of protein found in potatoes was affected by the concentration of nitrate fertiliser added to the crop when it was growing.
Using the information in the graph, which molecule do the potatoes make more of when the concentration of nitrate fertiliser increases?
A) amino acids
B) cellulose
C) fat
D) starch
▶️ Answer/Explanation
Ans: A
The graph indicates that as nitrate fertiliser concentration increases, the percentage of protein in potatoes also increases. Since proteins are made up of amino acids, the correct answer is A (amino acids).
Cellulose (B) is a structural carbohydrate, fat (C) is a lipid, and starch (D) is a storage carbohydrate. None of these are directly synthesized from nitrates, unlike proteins.
Topic – 7.1
Which food would add more fibre as part of a balanced diet?
A) black beans
B) cheese
C) eggs
D) tuna fish
▶️ Answer/Explanation
Ans: A
Black beans (A) are a rich source of dietary fibre, unlike cheese (B), eggs (C), and tuna fish (D), which contain little to no fibre. Fibre is essential for digestion and maintaining a healthy gut, making A (Black beans) the correct choice.
Topic – 7.2
The diagram shows the human digestive system.
Which letter represents the rectum?
▶️ Answer/Explanation
Ans: C
The rectum is the final section of the large intestine, where feces are stored before elimination. In the diagram, it is the terminal part (C) located just before the anus.
Other labelled parts include the stomach (A), small intestine (B), and appendix (D). The rectum’s position and function distinguish it from these structures.
Topic – 7.5
The bacterium Salmonella enterica can cause severe food poisoning, and the lining of the alimentary canal may be damaged. This damage affects the absorption of digested food.
Which region of the alimentary canal is most affected by this type of food poisoning?
A) colon
B) ileum
C) oesophagus
D) stomach
▶️ Answer/Explanation
Ans: B
The ileum is the primary site for nutrient absorption in the small intestine, where villi and microvilli increase surface area. Salmonella enterica damages the intestinal lining, impairing absorption.
The colon (A) mainly absorbs water, not digested food. The oesophagus (C) and stomach (D) are involved in food transport and digestion, not absorption. Thus, the correct answer is B (ileum).
Topic – 7.5
In which part of the alimentary canal is the most water absorbed?
A) colon
B) rectum
C) small intestine
D) stomach
▶️ Answer/Explanation
Ans: C
The small intestine is the primary site for water absorption in the alimentary canal, absorbing about 90% of the water from digested food.
While the colon (A) absorbs some remaining water, the small intestine (C) is responsible for the majority. The rectum (B) stores feces, and the stomach (D) primarily breaks down food, absorbing minimal water.
Thus, the correct answer is C (small intestine).
Topic – 8.3
The diagram shows the pathway of water molecules through a leaf and out to the environment.
mesophyll cell → process X → air space → process Y → stomata
Which statements are correct?
- Process X is active transport.
- Process X is evaporation.
- Process Y is diffusion.
- Process Y is osmosis.
A) 1 and 3
B) 1 and 4
C) 2 and 3
D) 2 and 4
▶️ Answer/Explanation
Ans: C
Process X (mesophyll cell → air space): Water evaporates from the mesophyll cell surfaces into the air spaces. This is evaporation (Statement 2), not active transport (Statement 1 is incorrect).
Process Y (air space → stomata): Water vapor diffuses out through the stomata. This is diffusion (Statement 3), not osmosis (Statement 4 is incorrect).
Since Statements 2 and 3 are correct, the answer is C (2 and 3).
Topic – 9.3
The diagram shows blood vessels entering and leaving some organs in the human body.
Which row identifies the pulmonary artery and the renal vein?
▶️ Answer/Explanation
Ans: A
The pulmonary artery carries deoxygenated blood from the heart to the lungs (vessel X), while the renal vein carries filtered blood away from the kidneys (vessel W).
Option A correctly identifies:
- X as pulmonary artery (only artery carrying deoxygenated blood)
- W as renal vein (carrying blood from kidneys to vena cava)
Other options are incorrect because they either reverse these vessels or misidentify Y (aorta) or Z (vena cava) as the target vessels.
Topic – 10.1
When a pathogen enters the blood, the number of white blood cells increases.
Some possible reasons why this happens are listed.
- It increases the number of antibodies.
- It increases the transport of oxygen.
- It increases phagocytosis.
- It increases the number of platelets.
Which reasons are correct?
A) 1 and 3
B) 1 and 4
C) 2 and 3
D) 2 and 4
▶️ Answer/Explanation
Ans: A
When pathogens enter the blood, white blood cells (WBCs) multiply to fight infection. Lymphocytes produce antibodies (1), and phagocytes engulf pathogens (3). Oxygen transport (2) is handled by red blood cells, and platelets (4) are involved in clotting, not pathogen defense. Thus, the correct reasons are 1 and 3 (Option A).
Topic – 20.3
The graph shows how waste is disposed of in three cities.
Which statement describes waste disposal in all of the three cities?
A) Burning is the second most common form of waste disposal.
B) Landfill is the main form of waste disposal.
C) More waste is burnt than recycled.
D) Recycling and burning together are the main forms of waste disposal.
▶️ Answer/Explanation
Ans: C
In all three cities, the graph shows that the percentage of waste burnt (orange bars) is consistently higher than the percentage recycled (blue bars). This makes statement C correct.
Statement A is false (burning is not always second), B is false (landfill is not the main method in City 3), and D is false (recycling + burning do not dominate in all cities). Thus, C is the only universally true statement.
Topic – 11.1
Which structure connects directly to the alveoli?
A) bronchus
B) bronchiole
C) larynx
D) trachea
▶️ Answer/Explanation
Ans: B
The respiratory pathway progresses as: trachea → bronchi → bronchioles → alveoli. Bronchioles (B) are the final branching airways that connect directly to alveoli, where gas exchange occurs.
The trachea (D) and bronchi (A) are larger, more proximal airways, while the larynx (C) is part of the upper respiratory tract. Thus, the correct answer is B (bronchiole).
Topic – 12.2
What is the equation for aerobic respiration?
A) glucose + carbon dioxide → oxygen + water
B) glucose + oxygen → carbon dioxide + water
C) water + carbon dioxide → glucose + oxygen
D) water + oxygen → glucose + carbon dioxide
▶️ Answer/Explanation
Ans: B
The balanced chemical equation for aerobic respiration is:
\( C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy} \)
Glucose (C6H12O6) reacts with oxygen (O2) to produce carbon dioxide (CO2), water (H2O), and energy (ATP). This matches option B.
Options A, C, and D incorrectly reverse the reactants and products or misrepresent the process.
Topic – 14.3
Which hormone is secreted by the pancreas?
A) adrenaline
B) insulin
C) oestrogen
D) testosterone
▶️ Answer/Explanation
Ans: B
The pancreas secretes insulin (B), a hormone that regulates blood glucose levels by promoting the uptake of glucose into cells.
Adrenaline (A) is produced by the adrenal glands, while oestrogen (C) and testosterone (D) are sex hormones secreted by the ovaries and testes, respectively. Thus, the correct answer is B (insulin).
Topic – 14.5
What is an example of phototropism?
A) a chemical produced by a plant
B) a painful sensation in response to a stimulus
C) the growth of a plant root towards the centre of the Earth
D) the growth of a plant shoot towards light
▶️ Answer/Explanation
Ans: D
Phototropism is the growth response of a plant to light. Option D describes this phenomenon correctly, as plant shoots grow towards light to maximize photosynthesis. The other options describe different concepts: A refers to plant chemicals (hormones), B describes a sensory response in animals, and C is an example of gravitropism (response to gravity).
Topic – 10.1
The graph shows changes in the resistance of the bacterium Escherichia coli to two different antibiotics between 2005 and 2023.
Which statement describes the changes that occurred between 2005 and 2023?
A) Between 2010 and 2015, the percentage of bacteria resistant to antibiotic 2 increased by 6%.
B) Between 2011 and 2016, the percentage of bacteria resistant to antibiotic 1 continually increased.
C) Between 2016 and 2023, the percentage of bacteria resistant to antibiotic 2 continually decreased.
D) Between 2020 and 2022, the percentage of bacteria resistant to antibiotic 2 decreased.
▶️ Answer/Explanation
Ans: A
From the graph, antibiotic 2 resistance increased from ~12% (2010) to ~18% (2015), showing a 6% rise (A is correct). Option B is incorrect as resistance to antibiotic 1 decreased between 2012-2014. Option C is wrong as antibiotic 2 resistance fluctuated (not continual decrease). Option D is incorrect as resistance increased from ~20% to ~22% (2020-2022).
The only accurate statement is A, confirmed by direct graph analysis of the specified time periods.
Topic – 16.2
The nuclei of which two structures fuse during fertilisation?
A) two eggs
B) two embryos
C) two gametes
D) two zygotes
▶️ Answer/Explanation
Ans: C
During fertilisation, the nuclei of two gametes (sperm and egg) fuse to form a diploid zygote. This is a fundamental process in sexual reproduction.
Option A is incorrect because two eggs cannot fuse. Option B is incorrect as embryos are multicellular and formed post-fertilisation. Option D is incorrect because zygotes are the product of fertilisation, not the structures that fuse. Thus, the correct answer is C (two gametes).
Topic – 16.3
Which statements about sexual reproduction in plants are correct?
- Anthers in wind-pollinated flowers are inside the flower.
- Pollen grains in insect-pollinated flowers are large and sticky.
- The stigma in insect-pollinated flowers is outside the flower.
A) 1 and 2
B) 1 only
C) 2 only
D) 3 only
▶️ Answer/Explanation
Ans: C
Statement 1: False – Anthers in wind-pollinated flowers are exposed (not inside) to release pollen easily.
Statement 2: True – Pollen grains in insect-pollinated flowers are large and sticky to attach to pollinators.
Statement 3: False – The stigma in insect-pollinated flowers is inside the flower to catch pollen from visiting insects.
Only Statement 2 is correct, so the answer is C (2 only).
Topic – 16.3
Which structure is found in both animals and plants?
A) cornea
B) ovary
C) sepal
D) stamen
▶️ Answer/Explanation
Ans: B
Option B (Ovary): Both plants and animals have ovaries. In plants, ovaries are part of the flower and develop into fruits after fertilization. In animals, ovaries produce eggs and hormones like estrogen.
Other options: The cornea (A) is exclusive to animal eyes, while sepals (C) and stamens (D) are flower structures found only in plants.
Thus, the correct answer is B (Ovary), as it is the only structure common to both kingdoms.
Topic – 17.1
Which sex chromosomes are present in a human sperm cell?
A) both X and Y chromosomes
B) either X or Y chromosomes
C) only X chromosomes
D) only Y chromosomes
▶️ Answer/Explanation
Ans: B
Human sperm cells are haploid gametes containing either an X chromosome or a Y chromosome, but never both. This is due to the separation of sex chromosomes during meiosis.
Option B is correct because:
- 50% of sperm carry X chromosomes (producing female offspring when fertilizing an egg)
- 50% carry Y chromosomes (producing male offspring)
Other options are incorrect because sperm cannot contain both chromosomes (A), and neither X-only (C) nor Y-only (D) populations exist – both types are normally produced.
Topic – 17.1
What are alleles made of?
A) amino acids
B) DNA
C) genes
D) protein
▶️ Answer/Explanation
Ans: B
Alleles are different versions of the same gene that determine variations in inherited characteristics. They are composed of DNA (B), the genetic material that carries instructions for protein synthesis. While genes (C) are segments of DNA, alleles specifically refer to alternative forms of a gene. Amino acids (A) and proteins (D) are products of gene expression, not the alleles themselves.
Topic – 18.1
The graph shows the percentage of a population with different phenotypes for the same characteristic.
Which characteristic in humans is represented by X?
A) ABO blood groups
B) arm length
C) height
D) mass
▶️ Answer/Explanation
Ans: A
The graph shows discrete categories (distinct bars), which is characteristic of ABO blood groups (A, B, AB, O). These are determined by specific alleles and show no intermediate values.
Options B, C, and D (arm length, height, mass) are continuous traits that would display a smooth bell curve, not separate bars. Thus, A is the correct answer.
Topic – 19.1
Energy transfers in an ecosystem are listed.
Which transfers are correct?
A) 1,2 and 3
B) 1 and 2 only
C) 1 and 3 only
D) 2 and 3 only
▶️ Answer/Explanation
Ans: A
All three energy transfers shown are correct in ecosystems: (1) Light to producers via photosynthesis, (2) Producers to primary consumers through feeding, and (3) Primary to secondary consumers in the food chain.
These represent the fundamental energy flow through trophic levels, making A (1, 2 and 3) the correct answer. Energy is never created or destroyed, just transferred between organisms.
Topic – 19.2
Which diagram shows the correct order in a food chain?
▶️ Answer/Explanation
Ans: C
A proper food chain always follows the energy flow:
Producer → Primary Consumer → Secondary Consumer → Tertiary Consumer
Option C correctly shows this sequence, typically represented as:
Plant (Producer) → Herbivore (Primary Consumer) → Carnivore (Secondary Consumer) → Top Carnivore (Tertiary Consumer)
The other options either reverse the order or mix up the trophic levels, making C the only correct representation of energy transfer in an ecosystem.
Topic – 19.3
Which process removes carbon dioxide from the atmosphere?
A) combustion
B) decomposition
C) photosynthesis
D) respiration
▶️ Answer/Explanation
Ans: C
Photosynthesis (C) is the process by which plants, algae, and some bacteria use sunlight to convert carbon dioxide and water into glucose and oxygen. This removes CO₂ from the atmosphere.
Combustion (A) and respiration (D) release CO₂, while decomposition (B) also typically releases CO₂ as organic matter breaks down. Therefore, the correct answer is C (photosynthesis).
Topic – 19.4
The graph shows how the population of the world has increased over time.
Which growth curve phase is represented by region P?
A) death phase
B) exponential (log) phase
C) lag phase
D) stationary phase
▶️ Answer/Explanation
Ans: B
Region P shows a steep, upward-curving trend, characteristic of the exponential (log) phase (B) where population grows at an accelerating rate. This differs from: the lag phase (C) with slow initial growth, stationary phase (D) where growth stabilizes, and death phase (A) which shows population decline. The rapid growth pattern matches the exponential phase of population growth curves.
Topic – 20.1
How do herbicides help to increase food production?
A) by increasing biodiversity
B) by killing insect pests
C) by providing nutrients
D) by reducing competition
▶️ Answer/Explanation
Ans: D
Herbicides increase food production primarily by eliminating weeds (D: reducing competition). This allows crops to access more water, nutrients, and sunlight without competing with unwanted plants.
Option A is incorrect as herbicides typically reduce biodiversity by targeting specific plants. Option B describes insecticides, not herbicides. Option C is false as herbicides don’t provide nutrients; fertilizers do.
Topic – 12.3
Which product of anaerobic respiration in yeast is used as a biofuel?
A) carbon dioxide
B) ethanol
C) glucose
D) oxygen
▶️ Answer/Explanation
Ans: B
During anaerobic respiration (fermentation), yeast converts glucose into ethanol and carbon dioxide. Ethanol (B) is widely used as a biofuel in industries and transportation.
Carbon dioxide (A) is a byproduct, not a fuel. Glucose (C) is the reactant, and oxygen (D) is not produced in anaerobic respiration. Thus, the correct answer is B (ethanol).
Topic – 21.3
Which statement describes genetic modification?
A) changing the genetic material of an organism
B) changing the genetic material of plants only
C) producing new organisms through fertilisation
D) selective breeding of organisms
▶️ Answer/Explanation
Ans: A
Genetic modification (GM) involves directly altering the DNA of an organism, which can include plants, animals, or microorganisms.
Why A is correct: It broadly covers all organisms, not just plants (B).
Why others are incorrect:
– B: GM applies to all organisms, not exclusively plants.
– C: Describes sexual reproduction, not genetic engineering.
– D: Refers to artificial selection over generations, not direct DNA manipulation.
Thus, the accurate definition is A (changing the genetic material of an organism).