Which of these sets of physical characteristics is used to classify animal groups

Covered in Fur

Explanation:

The kind of body covering an animal has is a physical characteristic. In this example, the animal is covered in fur. Objects or living things can be classified (grouped) by their physical characteristics

it enhances antibody production by t cells of the adaptive immune system.

hope i'm right

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