I need help on c and d

c)

In a feudal system, a peasant or worker known as a vassal received a piece of land in return for serving a lord or king, especially during times of war. Vassals were expected to perform various duties in exchange for their own fiefs, or areas of land.

D)

Feudalism's environmental degradation pivoted on the lord-peasant relationship, which limited the possibilities for reinvestment in the land. Consequently, feudalism exhausted the soil and the labor power from which it derived revenues, rendering the population vulnerable to disease.

fair labor standards act

explanation:

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.