CBSE 2026 · Region 2 · Set 1 · Q21 · 2 marks
(a)Name the organ that forms a connection between foetus and the uterus of a pregnant human female.(ii)How does it support both nutrition and hormonal regulation?Give reasons for :(i)All copulations do not lead to pregnancy.(ii)Meiosis I in spermatogenesis and oogenesis are markedly different.
(a)
Name the organ that forms a connection between foetus and the uterus of a pregnant human female.
(ii)
How does it support both nutrition and hormonal regulation?
Give reasons for :
(i)
All copulations do not lead to pregnancy.
(ii)
Meiosis I in spermatogenesis and oogenesis are markedly different.
Marking-scheme solution
(i)
Placenta
(ii)
Nutrition: It facilitates the supply of nutrients to embryo.
Hormonal regulation: Acts as an endocrine gland and produces hCG /Human Chorionic Gonadotropin, hPL / Human Placental Lactogen, estrogen, progestogens.
(i)
Fertilisation can only occur if the ovum and sperms are transported simultaneously to the ampullary region / use of contraceptive devices / low sperm count or poor sperm quality / absence of ovulation / lactational amenorrhea / coitus interruptus / periodic abstinence
(Any Other Correct Reason)
(ii)
| Meiosis I in Spermatogenesis | Meiosis I in Oogenesis |
| Starts at puberty | Starts during embryonic stage |
| Results in production of two equal haploid secondary spermatocyte | Results in production of unequal haploid secondary oocyte and first polar body |
(Any One Correct Difference)
Human ReproductionFertilisation and ImplantationUnderstandvery_short_answermedium
More from Human Reproduction
- Explain the neuroendocrine mechanism involved in the process of parturition in a human female leading to the…2025 · asked 3×
- Select the option that gives the correct identification of ovum, morula and blastocyst in a human female…2024 · asked 3×
- Briefly explain the events of fertilisation and implantation in an adult human female. OR (i) Arrange the…2026 · asked 3×
- Read the following passage and answer the questions that follow. Spermatogenesis is an important primary sex…2024 · asked 3×
- The diagram given below shows a developmental stage of human embryo. Answer the following questions with…2023 · asked 3×
- Study the graph given below that represents the changes in the thickening of the uterine wall in women 'X'…2024 · asked 3×
- Explain the process of formation of placenta in a human female after the implantation of the blastocyst in…2025 · asked 3×
- (i) Explain any four devices that flowering plants have developed to encourage cross-pollination. (ii) Why do…2024 · asked 3×
CBSE Class 12 Biology past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.