Which best explains why blood and the cytoplasm of cells are mainly composed of liquid water?
a. water is a common substance and is readily available.
b. water is an important transport and reaction medium.
c. water prevents biological reactions from occurring readily.
d. water prevents turgor pressure from making the cells too rigid.

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.