Rigid skeletons are formed from materials including chitin (in arthropods), calcium compounds such as calcium carbonate (in stony corals and mollusks) and silicate (for diatoms and radiolarians).
Hello, Saleemsafwah12. The answer would be A - It is younger than the rock layer below. This is because the deeper you go, the older the rock is, opposed to the top layer being the youngest of them all. I hope I helped!! Have a great day.
<span>There are a small number of boys who, after possibly contracting mumps, could experienced decreased fertility in the future. Giving a mumps vaccine, since it's a weaker version of the virus, will allow the body to fight it off without the negative effects that could come with a full version of the illness.</span>