Sagot :
Answer: Fertilization occurs, a zygote undergoes mitosis, a baby's cells divide mitotically, meiosis produces sex cells that will participate in fertilization.
Explanation:
Incomplete questions, options are:
Meiotic cell division occurs as the zygote develops into a gamete, meiosis produce the sex cells that will participate in fertilization, a baby grows into an adult through uncountable meiotic divisions, fertilization occurs, a zygote undergoes mitosis, a baby's cells divide mitotically, mitosis produces gametes.
1. Fertilization occurs: Fertilization is the union of a human egg and sperm (male and female gametes), which usually occurs in the fallopian tube. The result is the formation of a zygote or fertilized egg, which initiates the development of the embryo. In this way, the genetic material of both gametes is also fused.
2. A zygote undergoes mitosis: The zygote is the union of the egg and the sperm. Each gamete contributes 23 chromosomes to form the genetic material of the future organism. The zygote starts to divide throught mitosis. Mitosis is a type of cell division that generates two genetically identical daughter cells and occurs in somatic cells (all cells in the body that are not gametes). Eventually, it divides into two blastomeres, then into 4, then into 8, and so on during the passage of the zygote along the fallopian tube towards the uterus. Subsequent divisions of the 12 cells give rise to the morula. Then, the blastocyst is generated, which is an embryo of between 5-7 days of development and is composed of a large number of cells that begin to differentiate.
3. A baby's cells divide mitotically: An embryo is a living being in the early stages of its development, from fertilization until the organism acquires the morphological characteristics of the species. In the specific case of the human being, the term applies until the eighth week after conception (fertilization). Cell divisions for development occur by mitosis. In this way, the embryo will grow and develop, forming tissues and organs through growth thanks to mitotic divisions.
4. Meiosis produces sex cells that will participate in fertilization: Meiosis is a type of cell division that occurs in the gonads for the production of gametes, whereby a diploid cell undergoes two cell divisions, that generates four haploid cells. Thus sperm and oocytes are produced to eventually fuse during reproduction to form a diploid zygote. Meiosis has certain differences from mitosis, since in this type of cell division, the daughter cells created are all genetically distinct from each other and from the parent cell. This is because a crossing over occurs between non-sister chromatids of homologous chromosomes to exchange genetic material. This ensures that each gamete produced has genetic variability.