Final answer:
DDT, a chemical compound used as an insecticide, may require further verification due to its complex history and impact on health and the environment.
Step-by-step explanation:
Verification of Definitions
The question poses which definition may require further verification using another source. To answer this:
A) Aerosol - A colloidal solution dispersed in the air.
B) Biomass - The total mass of organisms in a given area or volume.
C) DDT - A chlorinated organic compound used as an insecticide.
D) Ecosystems - A community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.
Assertions about DDT may require further verification since it is a chemical compound with historical and environmental significance. Information about its use, ban due to health concerns, and its impact on the environment may be complex and warrant additional sources for accuracy.