Answer:
each chiasma, the chromosomes break and rejoin, trading some of their genes.
Explanation:
They could be white or black. Black should be dominant, I guess, so 75% of offspring should be black.
As far as I know, the adrenal glands, when submitted under pressure such as the one described in the example, secrete a substance known as epinephrine which has the tendency of increasing the affected person's heart rate and breathing.
Answer:

Hope it helped,
Happy homework/ study/ exam!
Heat wave is a prolonged period of abnormally high temperatures, usually in association with humid weather.
D. This is to “proofread” the DNA