Whenever human activity generates a concentration of a substance in the environment sufficient to cause harm to living things,it is called:

A) a free good.
B) an external shock.
C) a result of human greed.
D) pollution.

Living Things

Organisms that display the characteristics of life, including growth, reproduction, and the ability to respond to their environment.

Pollution

The contamination of the natural environment, causing adverse effects on living beings and ecosystems.