Hint: It is a process in which the new organism is formed by combining the genetic material of two different individuals. The first step of this method involves the fusion of a sperm and an ovum.
The production of offspring by the fusion of male and female gametes is termed reproduction. We all know that human beings do sexual reproduction for the production of new individuals. Male gametes are called sperms and female gametes are called ova or egg cells. The male gamete is sperm and it is a smaller and mobile cell that meets up with the much larger and less mobile female gamete or ova.
When sperms come out through the penis during ejection, it comes in contact with an egg and one of the sperms may fuse with the egg. This fusion of the egg and the sperm in the Fallopian tube is called fertilization. During fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus, and thus, a fertilized egg or zygote is formed. The zygote is the beginning of a new individual, it then moves to the uterus to complete the gestation cycle ending with the fetus being born.
Vegetative propagation is the kind of asexual reproduction occurred in plants in which a new plant grows from a fragment of the parent.
Cell division is the method in which a parent cell divides into two or more daughter cells.
Respiration is the act of breathing in living organisms through inhalation and exhalation.
So, the correct answer is ‘reproduction’.
Note: Sperms are small unicellular structures with a head, middle piece, and tail. Both sperm and egg are only haploid cells and they only carry half of the chromosomes needed.