The number of fossils found, the fact that fossils are oftentimes just a cast/mold of the organism with no real remains, and no interbreeding.
As time moves forward, we still strive towards better methods to answer questions about extinct organisms.
Answer:
C. Sending a message to the pituitary gland to start producing a hormone when the levels in the body are too low
Explanation:
It's not A, because that's the nervous system, not endocrine.
It's not B, because homeostasis = balance, and not stopping production isn't balance
It's not D, because that's the nervous system again.
The endocrine system governs hormones.
