Kelp is a -- since it converts -- to organic energy by photosynthesis. Several physical properties of the ocean promote its growth: kelp requires -- and nutrients; and it lives in regions where waters are cool throughout the year. Kelp plays an important role in the ocean. It provides a -- for many species, such as sea otters that forage and raise babies in the kelp beds. It also acts as a -- for many organisms, such as the sea urchin. Kelp harvesting has many effects on both ecosystems and humans. Extensive harvesting -- populations of fish and other organisms that live in kelp forests. However, harvesting -- profits for companies that use kelp, such as those that produce -- , an additive used in food and cosmetics. Fill in the blanks.