Which of the following is the correct definition of carrying capacity?
a. the maximum number of populations a community can sustain
b. the number of humans there will be in 54 years
c. the amount of time it would take for a population to double
d. the number of individuals an environment can sustain

(a is wrong)

D. The number of individuals an environment can sustain.

Explanation:

A carrying capacity of an ecosystem can be define as the number of individuals of a population of a species which an ecosystem can support or sustain in terms of resources. If the population of a particular species exceeds the carrying capacity of the ecosystem the population may decline due to lack of resources.

thinking it would be physical characteristics

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.