CIE iGCSE Co-Ordinated Science B17.2 Selection Exam Style Questions Paper 3
Question
(a) Scientists record the mass of each baby at birth in one country.
The results are shown in Fig. 10.1
(i) Complete the sentences about the mass of babies at birth as shown in Fig. 10.1.
The lowest mass at birth was ……………………………………….. g.
The most frequent mass at birth was ……………………………………….. g.
Fig. 10.1 shows that mass of babies at birth is an example of continuous variation.
This is because there is a ……………………………………….. of phenotypes between two extremes.
A phenotype is defined as the ……………………………………….. features of an organism.
(ii) State one other example of continuous variation in humans.
(b) The statements A–E describe stages of natural selection.
They are not in the correct order.
A There is competition for resources.
B Those with adaptations best suited to their environment survive and reproduce.
C This process is repeated over several generations.
D There is variation in a population.
E Alleles are passed on to the next generation.
Complete the answer spaces to show the correct order.
One has been done for you.
(c) Alleles are made of DNA.
(i) Define the term allele.
(ii) State where alleles are found in a cell.
▶️Answer/Explanation
Ans : 10(a)(i) 800 (g) ;
2400 (g) ;
range / AW ;
observable / AW ;
10(a)(ii) height / AVP ;
10(b) D in first box ;
B, E, C ;
10(c)(i) a version of a gene ;
10(c)(ii) nucleus ;
Question
(a) A school investigates variation in one class.
Define the term variation.
(b) A class measures the height of each student.
Table 7.1 shows the results.
(i) Identify the most frequent height range shown in Table 7.1.
……………………………………………………………………………………… cm
(ii) Complete the sentence to describe how Table 7.1 provides evidence that height is an
example of continuous variation.
Choose words from the list.
Each word can be used once, more than once or not at all.
genotypes offspring phenotypes
six eight two
The results in Table 7.1 show there are a range of ………………………………… between ………………………………… extremes.
(iii) State one example of discontinuous variation.
(c) Fig. 7.1 is a photograph of a female lion.
The lion has very sharp, pointed teeth suitable for catching and eating other animals.
(i) State the term used to describe an animal that gets its energy from feeding on other animals.
(ii) Circle the correct words shown in bold to complete the sentences to describe how lions may have developed sharp, pointed teeth.
There was a range of different length teeth in the lion population.
The lions with sharp, pointed teeth were better at catching and killing other animals for food.
The lions without sharp, pointed teeth adapted / died / survived.
The lions with sharp, pointed teeth passed on their alleles / cells / sex to their offspring.
This occurred over many days / hours / generations until eventually, all the lions had sharp, pointed teeth.
(iii) State the name used to describe the process in (c)(ii).
▶️Answer/Explanation
Ans : 7(a) differences between individuals (of the same species) / AW ;
7(b)(i) 150.0–154.9 (cm) ;
7(b)(ii) phenotypes ;
two ;
7(b)(iii) tongue rolling / AVP ;
7(c)(i) carnivore ;
7(c)(ii) died ;
alleles ;
generations ;
7(c)(iii) natural selection ;