Science (086) — AI-generated practice question

(a) In sexual reproduction, DNA from two different individuals (mother and father) combines. During this process, variations arise from DNA copying errors and the mixing of parental genetic material. This produces offspring with new combinations of traits, generating far greater variation than asexual reproduction, where a single parent copies its DNA to produce nearly identical offspring.

(b) Variation is useful because if the environment changes drastically, at least some individuals with favourable variations will survive. For example, if water temperature rises due to global warming, heat-resistant bacteria in a population will survive and reproduce, keeping the species from being wiped out.

Source: Chapter 7, Section 7.1.1 — The Importance of Variation; Chapter 8, Introduction

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• Part (a) is worth ~1.5 marks: mention two parents, combining of DNA, and greater variation. The contrast with asexual (single parent, near-identical copies) strengthens the answer.
• Part (b) is worth ~1.5 marks: state the principle (survival when environment changes) and give the exact bacteria/global warming example from the textbook — examiners look for this specific example.
• Do not write vague points like "variation helps evolution"; stick to what the textbook says — survival of species over time.