Which statement correctly contrasts plant-like and animal-like protists?

• A. Plant-like protists are autotrophic and major primary producers; animal-like protists are heterotrophic and feed by ingestion
• B. Plant-like protists are heterotrophic; animal-like protists are autotrophic
• C. Both groups are primarily decomposers
• D. Both groups are always multicellular

Answer: (A)

The key idea is how these protists obtain energy and nutrients. Plant-like protists, such as many algae, are autotrophic: they use light to drive photosynthesis and produce organic matter from carbon dioxide. They’re major primary producers in many ecosystems, forming the base of aquatic food webs. Animal-like protists, or protozoa, are heterotrophic: they rely on ingesting other organisms or organic particles to obtain energy, feeding by phagocytosis or other engulfing methods.

That makes the described contrast the best one. It accurately ties plant-like protists to autotrophy and primary production, and it links animal-like protists to heterotrophy and ingestion-based feeding. The other statements don’t fit as well: plant-like protists aren’t generally heterotrophic, animal-like protists aren’t typically autotrophic, protists are not defined by decomposing roles, and they aren’t all multicellular—many are unicellular.