Question

Choose the correct sequence of events that occur in human reproduction.
a. Gametogenesis $\to$ Gastrulation $\to$ Insemination $\to$ Fertilization $\to$ Implantation $\to$ Parturition
b. Gametogenesis $\to$ Insemination $\to$ Gestation $\to$ Implantation $\to$ Fertilization $\to$ Parturition
c. Gametogenesis $\to$ Insemination $\to$ Fertilization $\to$ Implantation $\to$ Gestation $\to$ Parturition
d. Gestation $\to$ Gametogenesis $\to$ Insemination $\to$ Fertilization $\to$ Implantation $\to$ Parturition

Answer 1

As we all know, fertilization in human beings is the union of male and female gametes, which include sperm in males and ovum in females. In human beings, fertilization occurs in the ampullary-isthmic region of fallopian tubes in females and results in a diploid zygote.

Complete answer:
Oogenesis: The process by which diploid or haploid cells undergo cell differentiation and division to form mature haploid gametes is called gametogenesis. It takes place in the gonads (testes in males and ovary in females). The process by which male gametes sperms are produced is called spermatogenesis and the process by which female gamete ova is released is called oogenesis.
Insemination: The process of male partner ejaculating semen into the vagina of a female partner during copulation is known as insemination. Semen is a greyish white fluid which contains the spermatozoa, fructose and other enzymes that help for its survival. A sperm has a head, neck, middle piece, and tail. The head is covered with a cap-like structure called acrosome, it has an enzyme called hyaluronidase, it helps in fertilization.
Fertilization: When the single celled ovum (female gamete) fuses with a single celled sperm (male gamete), the formation of diploid zygote takes place. This process is called fertilization. The motile sperms from semen swim and pass through the cervix, enter the uterus and reach the ampulla and the ovary released by ovum is also transported to the ampulla and hence the fertilization takes place, and the zygote is formed.
Implantation: The blastomeres in the blastocyst start arranging into an outer layer called trophoblast and the inner group of cells get attached to trophoblast and hence the formation of inner cell mass. The trophoblast layer then gets attached to endometrium and inner cell mass gets differentiated as an embryo. As blastocyst gets embedded in the endometrium, implantation takes place followed by pregnancy.
Gestation period: The average duration of human pregnancy is 9 months which is generally called gestation period.
Parturition: Then comes the childbirth which is termed as parturition. Oxytocin is released during childbirth and acts on uterine muscles. The strong uterine contractions cause the birth of the baby.
Later, the mother undergoes various bodily changes and starts producing milk which is called lactation.
Hence, the correct answer is option (c).

Note: Humans reproduce sexually and are viviparous (internal fertilization).
Also, the sex of the baby is determined by the father as he carries XY chromosome and female carries XX chromosome.
Sometimes, during pregnancy the fetus develops outside and such pregnancies are painful and not successful. It is a very rare condition.