Chemical reactions convert to . In nonliving systems, the presence of a(n) allows the reaction to proceed very quickly and have a lower . In living systems, this function is carried out by proteins called .

reactants, products

catalyst

activation energy

enzymes

Chemical reactions convert reactants to products. In nonliving systems, the presence of a(n) catalyst allows the reaction to proceed very quickly and have a lower activation energy. In living systems, this function is carried out by proteins called enzymes.

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).