Answer:
Sexual Reproduction. ... Organisms that reproduce sexually by joining gametes, a process known as fertilization, must have a mechanism to produce haploid gametes. This mechanism is meiosis, a type of cell division that halves the number of chromosomes. Meiosis occurs only in gamete producing cells within the gonads.
Explanation:
I'd go with the third one because the products of both of them are oxygen and carbon dioxide.
Answer: C. Germ Theory
Explanation: Germ Theory states that most diseases are caused by the presence micro-organisms within the body.
Presently, it is the accepted scientific theory for many diseases.