<em>Compounds like the pesticide DDT may bring about the evolution of new strains of organisms by </em><em><u>acting as a natural selecting agent.</u></em>
Evolution is generally defined as a gradual change to the characteristics of organisms over a period of time.
<u>When DDT is used on a particular population of pest, those that are weak within the population die off, leaving only those that are strong within the population to survive and multiply. The DDT acts a selecting agent for the survival gene in the pest and the survived gene eventually evolve into a new, DDT-resistant strain pest in no time.</u>
Answer:Each muscle in the body is made up of cells called muscle fibers. Muscle fibers are long, thin cells that can do something that other cells cannot do—they are able to get shorter.