In our everyday life we are surrounded with thousands of different types of chemicals, most of which adversely affect the endocrine system. (fitnessandpower.com)
From item # 4 on the list above, you know that there are two basic types of chemical reactions, ones that release energy and ones that absorb energy. (shapesense.com)
The same type of chemical response creates all three types of pleasure. (techtimes.com)