How could serfs move up from the bottom of the social hierarchy?
a) most peasants were also serfs.
b) serfs were always below peasants in the medieval hierarchy
c) serfs worked in the manor house, and peasants worked on the land.
d) serfs had more freedom than peasants

c) Serfs worked in the manor house, and peasants worked on the land.

Explanation:

The servants worked in the mansion and peasants worked on the land, so the servants had more "perks" and for that reason, they could rise from the bottom of the social hierarchy.

Peasants were the people who took care of the land and agriculture in general. A peasant could own his own land, but it was more common for him to work for the feudal lord, receiving a plot of land to live and protect.

The servants, on the other hand, served the nobility and could live at court, although it was necessary to pay tribute, they had a better life.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.