_______ is a group of minute plants, and _____ is a group of minute animals important as food sources.

• A. Phytoplankton, Zooplankton
• B. Zooplankton, Phytoplankton
• C. Algae, Finfish
• D. Producers, Consumers

Answer: (A)

In aquatic ecosystems, phytoplankton are minute plants that perform photosynthesis and form the base of the food web as producers. Zooplankton are minute animals that feed on phytoplankton and other tiny organisms, and they serve as a crucial food source for many larger aquatic animals. This pairing—phytoplankton for the tiny plants and zooplankton for the tiny animals important as food sources—fits the description perfectly. The other options mix categories that don’t align with both parts of the statement: zooplankton are animals, not plants; algae is a plant-like group but doesn’t capture the animal food-source role; finfish are larger fish, not a group of minute animals; producers and consumers are too general to match the specific groups described.