Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these :

Explanation

Enzymes control all the life processes. They increase the rate of a biological reaction. The magnitude of increase may be greater than those affected by other catalysts.Vitamins are accessory indispensable food factor, organic in nature (organic acid, amino acid esters, alcohols, steroids, etc.) required by an organism in small amounts to maintain normal growth and regulate the metabolic processes. Hormones are a biologically active organic substance that is produced in minute quantities by some specialized organs and exert physiological effects at sites remote from their origin.