In a biological reaction involving an enzyme, what does the substrate bind to? the active site of another substrate the inactive site of an enzyme the inactive site of another substrate the active site of an enzyme

The part of the enzyme where the substrate binds is called the active site (since that's where the catalytic “action” happens). ... Thanks to these amino acids, an enzyme's active site is uniquely suited to bind to a particular target—the enzyme's substrate or substrates—and help them undergo a chemical reaction. To catalyze a reaction, an enzyme will grab on (bind) to one or more reactant molecules. These molecules are the enzyme's substrates. In some reactions, one substrate is broken down into multiple products. ... The products then leave the active site of the enzyme.

Explanation:

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.