When mammals get an infection, their internal body temperature often rises 2 to 3 degrees Celsius. The body gets the energy it needs to react to an infection by —

increasing the rate of cellular respiration in mitochondria

Explanation:

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