What is an enzyme and what is biochemistry and what is enzyme theory?

An enzyme is a protein which acts as a biological catalyst. Biochemistry is the study of chemical processes within or related to living organisms and enzyme theory is the different theories on how enzymes work, either with 'lock and key' method or enzyme-substrate complex theory.

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.