Describe pregnancy and embryonic development.

Pregnancy can be best defined as the state of carrying a developing embryo or fetus inside the female body. positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray are some common ways to confirm pregnancy.The gestation period of humans are about 266 days (38 weeks, 9 months). There are three stages of pregnancy- The first trimester which covers the 1st week to 14th week The second trimester covers the week 15-26 The third trimester covers week 27-40. Embryogenesis can be best defined as the process of development of the foetus from the zygote. It is also known as embryonic development. It starts with the fertilization of an egg (ovum) by a sperm cell (spermatozoon). This results in the formation of zygote. Then the zygote undergoes a series of mitotic divisions leading to the formation of an embryo.It is a highly detailed and compound process, in which a single cell differentiates and develops into a multicellular human being. A continuous process in which there is the fertilization of an egg (ovum) by a sperm cell (spermatozoon) form a zygote which divides and differentiates into a definitive organ system and thereafter into their early functional stage.

Explain cell division during gamete formation.

Gametes are haploid. The parent plant body can be either haploid or diploid. All animals are diploid. A haploid parent produces gametes by mitotic division, whereas a diploid parent produces gametes by meiotic division. Many organisms belonging to monera, fungi, algae and bryophytes have haploid plant body. But organisms belonging to pteridophytes, gymnosperms, angiosperms and most of the animals have diploid parent body. In diploid organisms, specialized cells called meiocytes (gamete mother cell) undergo meiosis to produce gametes.