CIE iGCSE Co-Ordinated Science B17.1 Variation Exam Style Questions Paper 2
▶️ Answer/Explanation
Discontinuous variation (e.g. blood group, eye colour) is controlled by a single gene, so it results only from genetic differences.
Continuous variation (e.g. height, mass) results from an interaction of both genetic and environmental factors, so options A and B are incorrect.
✅ Answer: (D)
Continuous variation (e.g. height, mass) results from an interaction of both genetic and environmental factors, so options A and B are incorrect.
✅ Answer: (D)
▶️ Answer/Explanation
The black form of the moth first appeared as the result of a mutation, a random genetic change producing a new allele.
No human breeding programme selected the moths, so the shift in proportions is due to natural selection, not artificial selection.
Black moths were better camouflaged and survived better on polluted, darker tree bark, and pale moths survived better once pollution decreased.
✅ Answer: (D)
No human breeding programme selected the moths, so the shift in proportions is due to natural selection, not artificial selection.
Black moths were better camouflaged and survived better on polluted, darker tree bark, and pale moths survived better once pollution decreased.
✅ Answer: (D)
Question
Which human characteristic is not influenced by the environment?
A. blood group
B. height
C. shoe size
D. weight
▶️Answer/Explanation
Answer: A
Explanation: Blood group is determined genetically and is not influenced by environmental factors. Height, shoe size, and weight can all be affected by environmental factors such as nutrition and lifestyle.