Why does florida have a large number of underwater cave systems

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

How do living things obtain phosphorus

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere