Which statement about the size of the atom is true?

a The size of an atom is smaller than the size of a sand particle on a beach.
b The size of an atom is equal to the time in seconds since the formation of Earth.
c The size of an atom is large enough to be seen by the human eye.
d The size of an atom is somewhere between the length of a grasshopper and a bridge.

A= The size of an atom is smaller than the size of a sand particle on a beach.

The size is basically really really small, and you cannot see it in the naked human eye.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products