XX: the two X's look like chromosomes that pair up perfectly — females have a matching pair. XY: the Y looks like a little man standing with arms out — males have the odd one out. 'Why are boys different? Because of Y!'

What sex chromosomes do females and males have?

Females: XX (two X chromosomes). Males: XY (one X and one Y chromosome). These are the 23rd pair of chromosomes in humans.

Sample Questions

What determines the sex of a human baby?

A. The sex chromosomes inherited from the parents
B. The number of genes the baby has
C. Environmental factors during pregnancy
D. The age of the mother

1 markfoundation

Use a genetic diagram to show how sex is inherited in humans.

3 marksstandard

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