What type of organisms are photosynthetic algae?

Photosynthetic algae are primarily aquatic organisms that belong to the group of protists. They use sunlight to convert carbon dioxide and water into glucose and oxygen through the process of photosynthesis. Algae can vary in size from microscopic phytoplankton to large seaweeds and are crucial for aquatic ecosystems as they produce oxygen and serve as a primary food source for many marine organisms. They can be found in a range of environments, including freshwater, marine, and even moist terrestrial habitats.