Final answer:
The diploid cell destined for a specialized role in the production of gametes is the germ cell.
Step-by-step explanation:
The diploid cell destined for a specialized role in the production of gametes is the germ cell. In animals, sexually reproducing adults form haploid gametes from diploid germ cells. Fusion of the gametes gives rise to a fertilized egg cell, or zygote, which will undergo multiple rounds of mitosis to produce a multicellular offspring.