In the C and C++ programming languages, #pragma once is a non-standard but widely supported preprocessor directive designed to cause the current source file to be included only once in a single compilation.
During sexual reproduction, fertilization of the ovum (n, 23 chromosomes) by the sperm (n, 23 chromosomes) restores the diploid number and creates a zygote (2n, 46) (awww..) that divides and grows by mitosis to form a multicellular human.
What is the probability that a human sperm Cell will carry an X chromosome? How many chromosomes does a sperm or egg have?   Sperm and egg cells are haploid cells, meaning they have half the number of chromosomes as all other cells in the body. Humans have 46 chromosomes, so human reproductiveâ¦ cells will have 23.