Soft
Brain coral is a type of coral that looks somewhat like a brain. It is a hard coral.
Lettuce Coral, brain coral, elkhorn coral, staghorn coral, star coral, fire coral, sea pen, scroll coral, golfball coral, mustard hill coral, rose coral, sea whips, maze coral, rigid cactus coral, orange cup coral.... and many more.
Soft
http://www.wonder-okinawa.jp/006/english/hyakka/doubutu/sangorui/index.html Use that link to figure out which type of coral you need! If you just want the general name, though, use Cnidarians
The rarest type of coral is the Elkhorn coral.
Two types of coral that exhibit branching are fan coal and finger coral. Fan Coral: comes in many colors, has soft finger- like branching that is rounded at the ends. Finger Coral: distictively gray growing in thick colonies.
Vinyl can be as hard or soft as you want. You can make soft vinyl upholstery, or vinyl drain pipe so hard you can park a car on it without having it break.
Zooxanthellae are a type of dinoflagellate that live in the "skin" of hard coral. It's a symbiotic relationship where the zooxanthellae are photosynthetic and produce nutrients for the host coral.
The skeletons of dead corals are the foundation upon which layerer upon layer of successively younger animals attach themselves. The coral animal, or polyp, is colulmn shaped. Its lower end is attached to the hard floor made of the preceding coral skeletons of the reef, and its upper end extends into the water. There hard and soft corals, depending on the type of skeleton secreted. The hard-coral polyp deposits a cup-like solid skeleton of calcium carbonate around itself into which the polyp withdraws during the daytime. For this reason, deep sea divers see only the skeletons-and not the polyps-of hard corals.
Is it Hard rock or Soft rock
Gravel is not a type of rock. It is a general term for a size of small crushed rock. It can be fairly soft (limestone) or fairly hard (basalt, granite)
Pullip: Hard plastic Depending on the Obitsu body type: Hard plastic or Soft Vinyl