If a chromosome has 4 chromosomes in each sperm cell, its diploid number is

A sperm cell is a gamete, which contains haploid number of chromosomes. hence when it is diploid, the number will be 4x2=8 chromosomes.

What some science videos to you

1) the mayans built pyramids just like the egyptians. the mayans also used hieroglyphics like them.2) power was passed down by family. for example, if the father dies, the son would be the next king.3)they both built pyramids for their structures.4)the main crop for the mayans was maize.5)they also grew manioc, beans,  squash,  amaranth, and chile peppers.