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