Chairs = common noun; Roll-O-Rocker = proper noun. Harriet threw the stale cucumber sandwich in the trash can and fantasized about a Big Mac dripping with special sauce. Sandwich = common noun; Big Mac = proper noun. Because we like an attentive waiter, we always ask for Simon when we eat at Mama Rizzoli's Pizzeria.
Answer: Reef Sand is live sand when it is on the bottom of the ocean floor, it is here where the reef sand is alive. When the Reef Sand has been out of the seawater for a period of time and exposed to the airborne elements it is considered to be dead sand. (lacking nitrifying bacteria).
Structure. 1  A coral reef is actually a complex of features, only part of which is a living coral or algal framework, although the other associated features result from this live segment. The accumulations of carbonate sand and mud provide a habitat for sea grasses and mangroves and for almost inconspicuous blue-green algal mats.