D) Give one reason why only one sperm fertilizes the ovum​

because the ovum is made to fertilize only a sperm at a time, once a sperm enters it closes. It then divides to form twins, triplets and so on

that scientist would be robert hooke

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.