Zoology MCQs for NEET — Practice Questions with Answers

The text states: 'The zygote undergoes repeated mitotic division to form a blastocyst'. More specifically, under 2.5 Fertilisation and Implantation: 'The dividing embryo with 8-16 blastomeres is called a morula (Figure 2.11e). The morula continues to divide and transforms into blastocyst (Figure 2.11g) as it moves further into the uterus.'

The text states: 'The blastomeres in the blastocyst are arranged into an outer layer called trophoblast and an inner group of cells... The trophoblast layer then gets attached to the endometrium'.

From the 'REPRODUCTIVE HEALTH' chapter: 'The zygote or early embryos (with upto 8 blastomeres) could then be transferred into the fallopian tube (ZIFT–zygote intra fallopian transfer) and embryos with more than 8 blastomeres, into the uterus (IUT – intra uterine transfer)'.

The text explicitly states: 'Humans are sexually reproducing and viviparous.' (Chapter 2 intro) and also in the 'Fill in the blanks': '(a) Humans reproduce _____________ (asexually/sexually)' and '(b) Humans are _____________ (oviparous, viviparous, ovoviviparous)'.

The text under 'HUMAN REPRODUCTION' (Page 32) describes sperm structure: 'The sperm head contains an elongated haploid nucleus, the anterior portion of which is covered by a cap-like structure, acrosome. The acrosome is filled with enzymes that help fertilisation of the ovum.'

The text mentions: 'The zygote undergoes repeated mitotic division to form a blastocyst, which is implanted in the uterus resulting in pregnancy.' And also 'Zygote divides to form _____________which is implanted in uterus.'

Under '2.5 Fertilisation and Implantation', it is stated: 'As a result, the blastocyst becomes embedded in the endometrium of the uterus (Figure 2.11 step H). This is called implantation and it leads to pregnancy.'

The 'REPRODUCTIVE HEALTH' chapter describes IVF: 'In vitro fertilisation (IVF– fertilisation outside the body in almost similar conditions as that in the body)... in this method... ova... and sperms... are collected and are induced to form zygote under simulated conditions in the laboratory.'

According to the section on sperm structure (Page 32): 'The human male ejaculates about 200 to 300 million sperms during a coitus of which, for normal fertility , at least 60 per cent sperms must have normal shape and size and at least 40 per cent of them must show vigorous motility.'

The text states: 'Placenta also acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogens, progestogens, etc. In the later phase of pregnancy, a hormone called relaxin is also secreted by the ovary.' It specifically mentions relaxin from the ovary, not the placenta.