Which of the following is a diverse group of aquatic organisms capable of photosynthesising?

Algae

The correct answer is Option (4)- Algae

Algae are a diverse group of aquatic organisms that encompass a wide range of species, including unicellular and multicellular forms. They are capable of photosynthesis, utilizing sunlight to convert carbon dioxide and water into organic compounds, primarily carbohydrates, releasing oxygen as a byproduct. Algae play a crucial role in aquatic ecosystems as primary producers, providing food and oxygen for other organisms. They also contribute to nutrient cycling and serve as indicators of environmental health. Examples of algae include seaweeds, diatoms, and green algae.