On May 14, 1796, Jenner<span> took fluid from a cowpox blister and scratched it into the skin of James Phipps, an eight-year-old boy. A single blister rose up on the spot, but James soon recovered. On July 1, </span>Jenner<span> inoculated the boy again, this time with smallpox matter, and no disease developed. The </span>vaccine<span> was a success.</span>
my guess is B. I am probably wrong
In 1668, Francesco Redi, an Italian scientist, designed a scientific experiment to test the spontaneous creation of maggots by placing fresh meat in each of two different jars. ... Redi successfully demonstrated that the maggots came from fly eggs and thereby helped to disprove spontaneous generation.
Decomposers break down the remains of producers and consumers.
I believe your answer would be, it is a non-steroid hormone