Science (086) — AI-generated practice question

Both examples show that characteristics of an organism are determined by an interplay of genes and environment.

In human beings, sex is genetically determined — a child inheriting X from the father is a girl (XX), and one inheriting Y is a boy (XY). The genes alone decide the sex.

In contrast, in reptiles, environmental factors (like temperature) determine sex, showing that genes are not always in control.

This tells us that some traits are controlled primarily by genes, some primarily by the environment, and some by both together. Neither genes nor environment alone can explain all characteristics; the balance varies from organism to organism and trait to trait.

Source: Chapter 8, Section 8.2.4 – Sex Determination

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• The examiner wants you to use both examples — human sex determination (genetic) and reptile sex determination (environmental) — to draw a general conclusion.
• The key phrase to write is that genes and environment both play a role; which factor dominates depends on the organism and the trait.
• Avoid writing only about humans or only about environment — the question specifically tests whether you can synthesise both sides.
• "Genes vs environment" is a classic CBSE concept; stating that it is "not always one or the other" earns the concluding mark.