13. Populations of organisms grow at an rate, but factors such as food, habitat, predators, weather, disease, climate, & temperature can affect the maximum population size an area can support. 14. Sea otters are an example of a species where the effects of overhunting this population of organisms will severely affect the population #s of other species.

15. is determined by the # of species in a specific area as well as the # of different kinds of species in a specific area.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.