Insects have three pairs of legs or six legs. spiders have four pairs or eight legs and since centipedes have more then six legs, they are also not considered insects.
The answer is the letter b
Both kelps and coral reefs are composed of algae that grow in the shallow parts of the ocean in warm and sunny waters. However, kelp forest grows in nutrient-rich waters while corals can develop in low nutrient waters.
Kelp forests are therefore common where warm and cold current meet in an up-welling. Coral reefs are borne of a symbiotic relationship between coral polyps and algae. The coral forms a rigid carbon skeleton of calcium carbonate while kelps are long flexible algae plants.