Most of the marine animals have a stream lined body, which means, they have a sharp and pointed at the front. The pointed front of the organism allow to cut the resistance of the water. In case, the body is not pointed at the front and it is blunt, the water current and flow would resist the movement of the organism further. So, for the locomotion purpose, it is important to have a streamlined body. Further smooth and hair less body also decrease the resistance during the movement in the water.
Answer: B: the variety of living things on Earth.
(Biodiversity refers to every living thing, including plants, bacteria, animals, and humans.)
Answer:
Without the model, we can't help you. But a healthy coral reef would most likely have some kind of productive ecosystem.
Explanation:
I would assume the the diagram includes a reference to fish, algae or other plant-like life, and the coral itself. The coral polyps are in a symbiotic relationship with algae; the algae provide the polyps with energy via photosynthesis and the polyps build "homes" for the algae and other species living in the reef (the "home" for algae is literally the coral reef).
Other species like animal life use the reef as a place of protection against larger predators. Fish frequent reefs since many types of aquatic predators dislike shallow waters and coral reefs provide plenty of nooks and crannies to hide inside.