What pH must organisms maintain?

The pH value indicates the degree of acidity or alkalinity of a solution. In this case, the human body fluids. When the value is 0, the pH is acid, it is 14, we speak of an alkaline pH, and 7 indicates a neutral value. Inside the body, the pH may vary according to the body, and the specialists argue that do not have to be the same everywhere.

B"hf and f-"  is the correct answer took the test on edgenuity and got it right     

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).