Answers
8. Your answer is '2' placenta. It is an organ that develops in your uterus during pregnancy. This structure provide oxygen and nutrients to your growing baby and removes waste product from your baby's blood.
9. Your answer is ' d ' , that is female to find males more desirable.
The above following conditions are for the better copulatory condition that increases the chances of fertilization, like genital spine form a genital lock during copilation, while the copulatory plug is a gelatinous secretion using in the mating of some species.
10. Your answer is ' d ' . During spermatogenesis finally four spermatozoa are produced by meiosis second, while in Oogenesis finally one ovum is produced due to meiosis second. In Oogenesis process formation of polar bodies are takes place that decreases the number of ovum.
6. Your answer is 'c ' Gonadotropin releasing hormone ( GnRH ).After puberty age this hormone release by that hypothalamus that stimulate the anterior lobe of the pituitary gland to secrete FSH & LH hormone.
Both the hormone cause the gametogenesis and production of sex hormones in both male and female , and that causes development of sexual characters or transition from juvenile to adulthood.
8.In most of the mammals placenta provides nutrition for the fetal development.
ans: placenta
The placenta is a compound of embryonic and maternal tissues that provides nutrients to the developing embryo. The placenta is a unique organ, found only in mammals, allowing the mother to provide many nutrients to her offspring long before birth.
The placenta serves as a point of contact between the mother and the developing baby and has three main functions: Attach the uterus to the wall of the uterus
Provide nutrients to the fetus
Allow the baby to pass the waste into the mother's blood.
Yolk sac:
In the first pregnancy, the yolk sac serves as a source of nourishment for the developing baby. It is the first structure to appear within the gestational sac, covering the developing fetus and amniotic fluid. The uterus looks like a white spot around a clear area and can be seen on a transvaginal ultrasound - where the ultrasound wand is inserted into the vaginal rather than the abdomen - between three to five weeks' suspension.
Serosa:
The serous membrane (or serosa) is a smooth tissue membrane containing two layers of mesothelium, which secretes serous fluid. The inner layer that connects the organs (viscera) to the body's veins is called the visceral membrane.
The second layer of serous epithelial cells, called the parietal layer, overlaps the body wall. Between these two parts there is a potential, empty space except for a few millimeters of serous lubrication applied by two massage organs.
Amnion:
An amnion is a membrane that completely covers the embryo when first made. It fills in the amniotic fluid which causes the amnion to expand and become an amniotic sac that works to provide a protective environment to the embryo or uterus.
Mammary gland:
The mammary gland is a gland found in the breasts of women in the face of constipation, or milk production. Both male and female have muscle tissue inside the breasts; however, in women the glandular tissue begins to grow after puberty in response to estrogen release.