Answer: B. Environmental
Explanation: "Environmental means the protection of the natural world of land, sea, air, plants, and animals. Environmental means relating to or caused by the surroundings in which someone lives or something exists."
"Coral reef development occurs only in areas with specific environmental characteristics: a solid structure for attachment, relatively high water temperatures, clear waters low in phosphate and nitrogen nutrients, and moderate wave action to disperse waste and bring oxygen and plankton to the reef."