If a cell is selectively reducing the concentration of a particular enzyme in the extracellular fluid it will likely utilize

It is likely that it will utilize the receptor mediated endocytosis. The receptor mediated endocytosis is the one responsible for having to process absorption of the following substances such as the proteins, metabolites and hormones. It has the capacity to be utilized if a cell has reduce a concentration of an enzyme in an extra cellular fluid.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

b a mature ovary of a plant.