Phytoplankton, small sea-dwelling organisms, belong to which trophic level of the food web?

Primary producers

The correct answer is Option (3)-Primary producers

Phytoplankton belongs to the primary producers trophic level of the food web. Phytoplankton are microscopic, photosynthetic organisms that form the base of many marine and freshwater food chains. As primary producers, they utilize sunlight to perform photosynthesis, converting carbon dioxide into organic compounds. These compounds, rich in energy, serve as a food source for organisms at higher trophic levels, establishing the foundation of aquatic ecosystems.