Start learning →

Bihar Board Class 12 (Science) Reproduction in Organisms & Plants — practice questions — page 5

Explore 143 free Reproduction in Organisms & Plants questions in Bihar Board Class 12 (Science) Biology. Open each question or exercise to read its content, reference answers and available explanation.

Practise Reproduction in Organisms & Plants with Quill →

Reproduction in Organisms & Plants questions and exercises with answers

Showing questions 121–143 of 143.

The hormone that drives uterine contractions during childbirth (parturition) is:Read the answer and worked solution →Ovulation in a typical 28-day human menstrual cycle occurs around dayRead the answer and worked solution →The hormone detected by home pregnancy tests isRead the answer and worked solution →Flip and pair: term with meaningRead the answer and worked solution →True or false: evidence for evolutionRead the answer and worked solution →Order the sequence the chapter sets outRead the answer and worked solution →OriginsRead the answer and worked solution →HIV (Human Immunodeficiency Virus) primarily attacks which cells of the immune system?Read the answer and worked solution →Which contraceptive method ALSO prevents sexually transmitted infections?Read the answer and worked solution →Two true, one falseRead the answer and worked solution →Spot the odd one outRead the answer and worked solution →Amniocentesis was BANNED for sex-determination purposes in India by:Read the answer and worked solution →Oral contraceptive pills (OCPs) work primarily by:Read the answer and worked solution →A typical angiosperm embryo sac hasRead the answer and worked solution →Human pregnancy lasts approximately:Read the answer and worked solution →Spermatogenesis occurs in the:Read the answer and worked solution →Flip and pair: term with meaningRead the answer and worked solution →The mature embryo sac (female gametophyte) in flowering plants typically has:Read the answer and worked solution →The tough outer wall (exine) of pollen grains is made ofRead the answer and worked solution →Oogenesis in humans beginsRead the answer and worked solution →Flip and pair: process with driverRead the answer and worked solution →Fertilisation in humans typically occurs in theRead the answer and worked solution →Estrogen and progesterone are primarily secreted by:Read the answer and worked solution →

Worked practice questions

The hormone that drives uterine contractions during childbirth (parturition) is:

  1. Oxytocin (via positive feedback)
  2. Insulin (during fasting)
  3. Glucagon (raises blood sugar)
  4. Adrenaline (fight-or-flight response)
Show answer and solution

Correct answer: A. Oxytocin (via positive feedback)

Oxytocin (from posterior pituitary) drives strong uterine contractions during parturition. **It operates via POSITIVE FEEDBACK:** contractions stimulate more oxytocin, escalating until birth.

Open this question →

Ovulation in a typical 28-day human menstrual cycle occurs around day

  1. day 1
  2. day 7
  3. day 14
  4. day 28
Show answer and solution

Correct answer: C. day 14

Ovulation around day 14 — triggered by a surge of LH. The egg is then viable for ~24 hours sperm can survive ~5 days, so fertile window is ~6 days around ovulation.

Open this question →

The hormone detected by home pregnancy tests is

  1. FSH
  2. LH
  3. hCG (human chorionic gonadotropin)
  4. oestrogen
Show answer and solution

Correct answer: C. hCG (human chorionic gonadotropin)

hCG is produced by the trophoblast / placenta starting around implantation. Detectable in urine ~10-14 days after fertilisation. Sustains the corpus luteum (and thus progesterone) until the placenta takes over hormone production.

Open this question →

How to practise

  1. Choose a Reproduction in Organisms & Plants question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Reproduction in Organisms & Plants practice for Bihar Board Class 12 (Science). Read explanations as you go. No signup form needed to start.

Practise Reproduction in Organisms & Plants →

More Biology topics

Biotechnology and ApplicationsGenetics and EvolutionBiology in Human Welfare & HealthSexual Reproduction in Flowering PlantsMolecular Basis of InheritancePrinciples of Inheritance and VariationHuman Health and DiseaseEvolution