Can leukopenia cause a positive tb blood test

Can someone give me one specific health problem, and explain it. !

True or false mucous membranes destroy pathogens on the outer body surface, at body openings.

Melanocytes and keratinocytes work together in protecting the skin from uv damage when keratinocytes a. provide the melanocyte with a protective shield against abrasion b. maintain the appropriate temperature so the product of the melanocyte will not denature c. maintain the appropriate ph in order for the melanocyte to synthesize melanin granules d. accumulate the melanin granules on their superficial portion, forming a uv-blocking pigment layer