Which structure fuses to form a diploid zygote during sexual reproduction?

The correct answer is male (+) haploid cell and female (-) haploid cell fuse to form a diploid zygote during sexual reproduction.

Explanation:

Sexual reproduction is the process that involves two processes- first is meiosis, involves the division of the number of chromosomes to half, and fertilization, the process of the fusion of two gametes or haploid cells and the maintaining or restoring of the original number of chromosomes.

In sexual reproduction, the specialized haploid cells or gametes from two different individuals, termed as the (+) and (−) mating types, join to form a diploid zygote.

thus, the correct answer is male (+) haploid cell and female (-) haploid cell.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.