Describe the structure of human sperm.

Sperms are haploid male gametes that are produced in the seminiferous tubules of a male testis. Sperm cells are motile (capable of moving) and swim their way to the female gamete through the female reproductive tract. A sperm cell is a long, thin and elongated structure with a head, a middle piece and a tail. Head: The sperm head is a conical structure made up of acrosome at the tip and the haploid nucleus. Neck: It is a narrow, constricted area between the head and the middle piece. Middle piece: The region containing many mitochondria to provide energy to the sperm for motility. Tail: The flagellar tail provides propulsion movement so that the sperms can move in the forward direction.

Explain "Implantation".

Implantation is the term used to denote the process of attachment of blastocyst to the endometrium of the uterine wall. This event takes place after 7th day of fertilization of the sperm with the egg in the fallopian tube.

Mother's milk is considered very essential for the newborn infant explain with reason.

At the time of pregnancy, the mammary glands of females undergo differentiation and start producing milk which is called lactation and this helps in feeding the newborn. The mother’s first milk is called colostrum, which is yellow coloured and is rich in IgA. These antibodies provide protection to the infant from various diseases. It also prevents allergies in infants. Breast milk is rich in nutrients like fats, casein, lactose, mineral salts, etc which are essential for the growth of the baby. Hence, breastfeeding is recommended during the initial period of an infant's growth for bringing up a healthy baby.

What will be effect on embryonic development if placenta does not formed after implantation. Explain.

The placenta is a temporary organ that is formed only during pregnancy. It is a link between the maternal uterine wall and the developing embryo or foetus. It helps to provide oxygen and nutrients to the foetus while removing carbon dioxide and other waste products from foetal blood. These materials are exchanged between the maternal and foetal blood by diffusion. It also produces some hormones and also protects the foetus from harmful microorganisms and infections. If the placenta does not form after implantation, it can affect the developing baby's growth. It cannot grow and develop normally in the uterus and didn't get enough oxygen and nutrients. The waste materials are also not removed that cause the infection. It also causes the complications during pregnancy and delivery.