Which of the following is known as the primary type of plankton that is photosynthetic?

Phytoplankton is recognized as the primary type of plankton that is photosynthetic. These microscopic organisms, which include various types of algae and cyanobacteria, play a crucial role in the aquatic food web and are responsible for a significant portion of the world's oxygen production through photosynthesis. They use sunlight to convert carbon dioxide and water into sugars and oxygen, forming the base of the marine food chain. The photosynthetic capabilities of phytoplankton allow them to thrive in well-lit upper layers of oceans and lakes, where they contribute to both energy production and carbon cycling in aquatic ecosystems.

In contrast, micro plankton includes both phytoplankton and zooplankton, and psyliaplankton is not a recognized category of plankton. Zooplankton, on the other hand, are primarily heterotrophs that feed on phytoplankton or other organic materials. This distinction emphasizes the unique role that phytoplankton plays in the ecosystem as a key producer of energy and oxygen.