Which of these is a biotic factor of an ecosystem?
the temperature of water in a stream
a the amount of water vapor present in a rain forest
b the bacteria that live in the intestine of a rabbit
c the rocks that provide cover for a rattlesnake

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

In a population that is in hardy-weinberg equilibrium, there are two possible alleles for a certain gene, a and a. if the frequency of allele a is 0.4, what fraction of the population is heterozygous? a. 0.40 b. 0.60 c. 0.16 d. 0.48

What are the pros and cons of quadrat sampling?