The short, hair-like structures that propel paramecium through the water are called:

these structure are called Cilia

this is a good question! i'll do some research and come back when i have the answer!

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