Answers- The correct statements about sea grasses are
1. They act as habitats for many marine species
2. They generate up to 10 liters of carbon a day and add nutrients to the sea. They have huge carbon reserves and posses 10 % of the ocean carbon. Also have much higher carbon holding capacity than forest.
3. They are a source of food for manatees and other herbivores - Sea grass in the major source of food for herbivores in marine environment
4. They are toxic to bacteria and algae and protect other organisms by inhibiting the growth of microorganisms.