8th Grade Science DST 3
Monday 20th November 2023
Chapter 3, Topic 1: Variation within a species
1. Name term used to describe variation that is caused by environmental factors (1
mark)
2. Give two examples of discontinuous variation (2 marks)
3. Explain why human weight is caused by both inherited and environmental factors. (2
marks)
4. The tally chart shows some lengths of beans. Some parts are missing. Complete the
chart. (6 marks)
Chapter 3, Topic 2: Chromosomes, genes, and DNA
5. What is DNA? (1 mark)
6. Anne swabbed her cheek cell and counted it to find chromosomes inside it, how many
would she expect to find? (1 mark)
Chapter 3, Topic 3: Fertilisation and inheritance
7. What is another term for sex cell? (1 mark)
8. The diagram below shows a human sperm cell and its structure. Label the five
missing parts. (5 marks)
9. Why does an egg cell contain a food store in its cytoplasm? (1 mark)
A = It protects the egg.
B = It contains nutrients for the developing embryo.
C = It contains the information for making a new animal.
D = It is a water reserve for the developing embryo
10. What are the combinations of sex chromosomes that determine the sex of a male
and female (2 marks)
11. Female egg cells contain X chromosomes. Explain how a male’s sperm cell determines
the sex of the baby. (2 marks)
Chapter 3, Topic 4: Fetal growth and development
12. Explain how fetal scanning can be used to improve scientists’ understanding of fetal
development and improve the care given to women during their pregnancy (3 marks)
13. What does the term embryo mean? (1 mark)
14. Why is it important for a pregnant woman to have a healthy, balanced diet? (1 mark)
15. Explain why a doctor might be concerned if a pregnant woman gets a virus (2 marks)
16. Josephine is expecting twins and recently gave up smoking. What are two harmful
effects on a fetus if a pregnant woman smokes during pregnancy? (2 marks)
Chapter 3, Topic 5: Natural selection
17. Complete the passage below using the words from this list. There may be words
left over. (2 marks)
extinction
evolution
variation
the ice age
fossil
mutation
Darwin’s theory of ___________explains how species have changed over time. The
theory is supported by evidence from observations of organisms and from
___________variation.
18. What does the term evolution mean? (1 mark)
A = a theory by Charles Dickens
B = a change in the environment
C = a theory by Charles Darwin
D = a change in something over time
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