your answer is given below..
The environment is rich in infectious agents that transmit disease through pathogens.
The correct answer for this question is this one: "c. J.J. Thompson." J. J. Thomson is the <span>scientist who designed an experiment that enabled the first successful detection of an individual subatomic particle. </span>J.J. Thomson<span> (Sir Joseph John Thomson, 1856-1940), who demonstrated in 1897 that "cathode rays" consisted of negatively-charged particles, later named electrons.</span>
It acts like a product. Think before actually putting this down but i think this is it.
The answer for this question should be D) or the fourth option Protists.