What can white blood cells do that them carry out their defensive functions more effectively?

Migrate through blood vessels

Explanation:

White blood cells have the ability to perform diapedesis. Diapedesis refers to the emigration of white blood cells through the blood vessels. During the process, white blood cells move along the endothelium of blood vessels and stick to it. The white blood cells squeeze between the endothelial cells to migrate out of the blood vessels.

In this way, white blood cells can reach the site of infection or move from blood to the interstitial fluid to perform immune functions. The ability to migrate in and out of the blood vessels allows the phagocytic neutrophils and macrophages to arrive at the site of pathogen entry, basophils arrive at the site of inflammation to perform their respective functions.

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

i believe your answer would be c.. : )