B. 245 million
from the end of Carboniferous Period to the beginning of the Triassic period
Answer: The endocrine system sends chemicals called hormones through the bloodstream to change short-term and long-term activities in the body
Explanation: Endocrine system is a system made up of glands that produce and secrete chemical signal called hormones which travel through the bloodstream to the target cell where they exert their effects.
A hormone is a chemical messenger secreted by an endocrine gland. Long-term activities in the body influenced by hormones include growth and development.
I would say that the answer to this question is most likely B or D.
