The number of individuals that the environment can support over a long period of time is its

Step 1: Analyze the question The question asks for the term describing the maximum number of individuals an environment can support sustainably over a long period.

Step 2: Explain the concept In ecology, every environment has limited resources such as food, water, shelter, and space. Because of this, a population cannot keep growing forever. The maximum population size that an environment can sustain indefinitely, without degrading the habitat, is called the carrying capacity (often written as K in population growth models).

When a population is small, it grows quickly (the J-shaped curve). As it nears the carrying capacity, growth slows because of competition, disease, predation, and shortage of resources. The population then levels off around K (the S-shaped or sigmoid curve).

Step 3: Evaluate the options

• A. Growth rate: This is how fast a population increases in size. It is not the limit the environment can support.
• B. Total capacity: This is not a standard ecological term.
• C. Population capacity: This is not the standard term either. It sounds close, but the correct term is "carrying capacity."
• D. Carrying capacity: This is the maximum number of individuals an environment can support over a long period. ✔

Step 4: Answer The correct option is D. carrying capacity.

Exam tip: Think of a bus. A bus has a fixed number of seats, and that is the number it can "carry" comfortably. In the same way, an environment "carries" only a certain number of organisms. Whenever you see "maximum population an environment can sustain," write carrying capacity.