Question

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

Answer 1

The answer would be: accumulate the melanin granules on their superficial portion, forming a UV-blocking pigment layer

The number of melanocyte cells is not much compared to keratinocytes. That is why melanocytes secrete dark melanin granules that will be spread into keratinocytes, not to itself.
The nutrient should be provided by the blood vessels of dermis skin. There should be no problem with pH or temperature either.