In the ocean, communities of plants, algae, and animals are distributed according to the depth of the water and distance from shore. light reaches organisms in the , where microscopic and multicellular algae provide food for the animal community. light levels in the are too low to support photosynthesis. the seafloor is called the . fishes and marine mammals swim in open water known as the . a distinctive biome called a(n) is found where a freshwater stream or river merges with the ocean.

Light reaches organisms in the photic zone, where microscopic Phytoplankton and multicellular algae provide food for the animal community. Light levels in aphotic zone are too low to support photosynthesis. The seafloor is called the Benthic realm. Fishes and marine mammals swim in open water known as the Pelagic realm. A distinctive Biome called an Estuary is found where a freshwater stream or river merges with the ocean.

Photic zone is the surface layer of the ocean that receives sunlight, which means it permits photosynthesis by plants and phytoplankton. In aphotic zone , there is no light, therefore the phytoplankton and algae can not grow and undertake photosynthesis, the carbon dioxide is accumulated, there is less Oxygen and the pH is lower than in the photic zone. 

They must use the scientific method

Ithink the answer is d.