Which is an internal environmental factor that affects heredity
a) light
b) temperature
c) nutrition
d) hormones

its hormones.. but i also explain why!!

Heredity is defined as the process of passing down the biological character from parent to offspring through genes. The hormones are commonly known as the body’s chemical messengers that have effect on various processes in the body including the mood. Humans behave differently and studies found that both heredity and hormones affects human behavior though in different ways. Hormones are responsible for a number of human functions which include development, growth, metabolism, etc.

I’m going to go with b!