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).
Reefs (aka Rainforest of the Sea) : Reefs are made of coral or rocky formations. Coral reefs are one of the most diverse marine habitats. Coral reefs are most commonly found at shallow depths in tropical waters, but deep water and cold water corals also exist on smaller scales in other areas.