20 Points!!!!!!!!!!!! Please Help!!!!

1. What does the term carrying capacity describe?
   

AThe maximum number of birth rates for a population.

BThe ability of a population to accept new immigrants.

CThe population size that the environment can sustain.

DThe ratio of birth rates to death rates in a population.

1. Which factor is a density-dependent limiting factor on the population of a species?
   

Apredation

Bunusual weather

Cnatural disasters

Dseasonal variation

1. Which nutrient cycle is most affected by the over-use of ammonia fertilizers on commercial farms, as well as by the accumulation of waste on cattle farms and feed lots?
   

Awater

Bcarbon

Cnitrogen

Dphosphorus