Why is Drosophila male fly referred to as heterogametic?

Explanation

**Step-by-Step Solution:**

1. **Understanding Drosophila**: Drosophila, commonly known as the fruit fly, is a model organism in genetics. It has a total of 4 pairs of chromosomes.

2. **Chromosome Composition**: Among these chromosomes, there are 2 pairs of large autosomes, one pair of small autosomes, and one pair of sex chromosomes.

3. **Sex Chromosomes in Drosophila**: The sex chromosomes are different for males and females. In females, the sex chromosomes are both X (XX), making them homozygous. In contrast, males have one X and one Y chromosome (XY), making them heterozygous.

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