Answer :
Final answer:
The complement pathway that is activated by binding of C3b to cell surfaces is the b.) alternative pathway.
Explanation:
The alternate pathway is initiated by the spontaneous hydrolysis of C3 in the absence of specific antibodies. When C3b binds to cell surfaces, it triggers a cascade of reactions that contribute to the immune response, including opsonization of pathogens and activation of inflammatory processes. This pathway provides a rapid and crucial defense mechanism against microbial invaders, complementing the classical pathway initiated by antigen-antibody complexes.