What is (are) the role(s) of complement proteins in the immune response?
I. They attract white blood cells to the site of infection.
II. They help other cells avoid infection.
III. They cause pathogens to clump together, making the pathogens easier to identify and destroy.
IV. They form a pore in the plasma membrane of a pathogen, causing it to rupture.
I only
II and IV only
II and III only
I and IV only
I, II, and IV only

Pathogens are recognized by a variety of immune cells, such as macrophages and dendritic cells, via pathogen-associated molecular patterns (PAMPs) on the pathogen surface, which interact with complementary pattern-recognition receptors (PRRs) on the immune cells' surfaces.

Explanation:

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.

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