Which term describes organisms that spend their entire life cycle as plankton?

• A. Macroplankton
• B. Holoplankton
• C. Meroplankton
• D. Microbial Loop

Answer: (B)

Holoplankton are organisms that spend their entire life cycle in the plankton, drifting with currents from birth to death and never transitioning to a benthic or nektonic adult. This contrasts with meroplankton, which only spend part of their life as plankton (usually as larvae) before becoming adults that live on the sea floor or swim actively. The size-based terms macroplankton and microplankton describe how big the organisms are, not how long they stay plankton, and the microbial loop is about how bacteria and other tiny organisms recycle dissolved organic matter—an ecological process, not a life-stage category. So holoplankton best match the idea of spending the entire life cycle as plankton.