RNAi is initiated by , which leads to the of specific genes.

c

explanation:

lichens that colonize bare rock secrete acids that break down the rock and start the soil-production process. so they expose rocks

prejudice, stereotyping, and discrimination often go hand-in-hand, but it is also possible to have one without the others. when an ethnic group is stereotyped with a neutral or positive attribute such as "family-oriented," prejudice and discrimination may not be involved.

explanation:

while prejudice refers to biased thinking, discrimination consists of actions against a group of people. discrimination can be based on age, religion, health, and other indicators; race-based laws against discrimination strive to address this set of social problems.