Melatonin is secreted by
A. the hypothalamus during the day
B. the pineal gland during the night
C. the autonomic nervous system during the winter
D. the thyroid gland during cold seasons

The answer would be B, the pineal gland during the night.

Explanation:

The secretion of melatonin is triggered by darkness, therefore produced during the night.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.