What is an active site? A )a gland that secretes a particular enzyme
B) a part of an enzyme molecule into which a substrate molecules fits
C)a part of the substrate to which an enzyme molecule attaches
D)a place in the body where an enzyme works

answer: - b cells

explanation: -

there are many types of white blood cells present in our body. one such class of white blood cells are the lymphocytes. the b cells belong to the lymphocyte class of wbcs. the b cells perform their action against the pathogen by producing specialised proteins called as antibodies. these antibodies are produced as and when the b cells encounter pathogens in response to the antigens present on the surface of the pathogen. these antibodies bind to the antigens present on the pathogen and then, target them for destruction by other cells of the immune system.

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.

Photo means light and synthesis means combination so combination of light

Yes yes yes very good