Answer:
8
Explanation:
The fly has only 3 pairs of somatic chromosomes, that means that only can combine 3 chromosomes. To calculate the combinations the exponential 2n it is used. In this case is 2 to the third power that is equal = 2 x 2 x 2 = 8
This fly also has a fourth pair, but this one is the sexual one, so the main function of this gene is to give the sex to the offspring.