A substrate molecule fits into the active site of an enzyme because of a match of _____. Chemistry homework help

1. A substrate molecule fits into the active site of an enzyme because of a match of _____.A. Number of atomsB. Molecular MassC. Molecular ShapeD. Melting points2.A sample of a metal on the atomic scale would best be described as a network of positive ions surrounded by free-flowing _________ .A. ElectronsB. ProtonsC. NeutronsD. Atoms