2. The phosphorus cycle is not
O atmospheric
O slow
O necessary

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.

this is a good question! i'll do some research and come back when i have the answer!

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.

characteristics of hydrocarbons