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(a) Giving two examples, justify the statement that the sex of the offspring in all animals is not always genetically determined.
(b) Differentiate between the sex chromosomes of male and female human beings.
(b) Differentiate between the sex chromosomes of male and female human beings.
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(a)
* In a few reptiles, the temperature at which fertilised eggs are kept determine whether the animal developing from the eggs will be male or female. (1 Mark)
* In snails, individuals can change sex. (1 Mark) (Any other example)
(b)
* Male sex chromosome: Male has a mismatched pair i.e, 'XY' chromosomes. (1 Mark)
* Female sex chromosome: Female has a perfect pair i.e. 'XX' chromosomes. (1 Mark)
* Male sex chromosome: Y chromosome is smaller than X chromosome. (1 Mark)
* Female sex chromosome: Both X chromosomes are of same size. (1 Mark) (Any one difference, Any other difference)
* In a few reptiles, the temperature at which fertilised eggs are kept determine whether the animal developing from the eggs will be male or female. (1 Mark)
* In snails, individuals can change sex. (1 Mark) (Any other example)
(b)
* Male sex chromosome: Male has a mismatched pair i.e, 'XY' chromosomes. (1 Mark)
* Female sex chromosome: Female has a perfect pair i.e. 'XX' chromosomes. (1 Mark)
* Male sex chromosome: Y chromosome is smaller than X chromosome. (1 Mark)
* Female sex chromosome: Both X chromosomes are of same size. (1 Mark) (Any one difference, Any other difference)