Which pair of organisms consists of producers?

Plants and phytoplankton

The correct answer is (a) Plants and phytoplankton.

Producers, also known as autotrophs, are organisms that can produce their own food using energy from sunlight or inorganic substances. They are the primary source of energy in ecosystems.

Plants are examples of terrestrial producers that use photosynthesis to convert sunlight into energy-rich organic compounds. Phytoplankton, on the other hand, are aquatic producers found in bodies of water, such as oceans and lakes. They also use photosynthesis to produce their own food and are an essential part of the marine food chain.

Option (b) Plants and consumers is incorrect because consumers are organisms that obtain their energy by consuming other organisms, including plants. They do not produce their own food.

Option (c) Zooplankton and phytoplankton is incorrect because zooplankton are consumers that feed on other organisms, including phytoplankton. Phytoplankton, as mentioned earlier, are the primary producers in aquatic ecosystems.

Option (d) Phytoplankton and chlorophylls is incorrect because chlorophylls are pigments found in plants and algae that facilitate the process of photosynthesis. While they are important for photosynthesis, they are not producers themselves.

Therefore, the correct choice is (a) Plants and phytoplankton, as both are examples of organisms that are capable of photosynthesis and are considered producers.