During meiosis II, separation of which structures occurs?
Answer: B
Meiosis II is similar to mitosis; sister chromatids separate at anaphase II, resulting in four haploid cells from the two haploid cells formed after meiosis I.
Q.102Easy
A 28-year-old male presents with azoospermia and is found to have a 47,XXY karyotype. What is this chromosomal abnormality called?
Answer: B
Klinefelter syndrome (47,XXY) is the most common male chromosomal abnormality, presenting with azoospermia, hypogonadism, gynecomastia, and infertility.
Q.103Easy
Which vitamin supplementation is crucial in the periconceptional period to reduce neural tube defects?
Answer: B
Folic acid supplementation (400 mcg minimum, higher for high-risk women) during the periconceptional period reduces neural tube defects by 50-70%.
Q.104Easy
In a typical 28-day menstrual cycle, ovulation occurs approximately on which day?
Answer: B
Ovulation typically occurs 14 days before the next menstruation. In a 28-day cycle, this corresponds to day 14 of the cycle, marking the middle of the proliferative phase.
Q.105Easy
Which of the following intrauterine devices (IUDs) releases hormones to prevent pregnancy?
Answer: B
The LNG-IUD releases levonorgestrel directly into the uterine cavity, causing endometrial atrophy and thickened cervical mucus, with effectiveness lasting 3-7 years.
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Q.106Easy
Which hormone is primarily responsible for initiating and maintaining spermatogenesis?
Answer: A
FSH directly stimulates Sertoli cells in seminiferous tubules to initiate spermatogenesis. While LH and testosterone support the process, FSH is the primary initiator.
Q.107Easy
Which of the following contraceptive methods has the highest failure rate?
Answer: C
Spermicides used alone have a failure rate of 18-28% with typical use. IUDs and implants have failure rates <1% with typical use.
Q.108Easy
Which stage of oogenesis is arrested at the time of ovulation?
Answer: B
The secondary oocyte is arrested in metaphase II at ovulation. It completes meiosis II only if fertilization occurs.
Q.109Easy
Which of the following STIs is most commonly associated with pelvic inflammatory disease (PID)?
Answer: B
Chlamydia trachomatis is the leading cause of PID, accounting for 30-40% of cases. Neisseria gonorrhoeae is the second most common cause.
Q.110Easy
A 29-year-old woman with regular 28-day cycles wants to use the rhythm method for contraception. Which days are considered the fertile window?
Answer: B
In a 28-day cycle, ovulation typically occurs on day 14. The fertile window includes 5 days before and 1 day after ovulation (approximately days 8-19), accounting for sperm survival and ovum viability.
Q.111Easy
Which of the following is a copper-containing IUD approved for use in India with the longest duration of effectiveness?
Answer: B
Copper T 380A has the longest duration of effectiveness (10-12 years) among copper IUDs approved in India, with the lowest failure rate of 0.6-0.8%.
Q.112Easy
Which of the following hormonal changes is MOST characteristic of the luteal phase of the menstrual cycle?
Answer: B
The luteal phase is characterized by high progesterone levels secreted by the corpus luteum. Estrogen levels are moderate but lower than follicular phase peak.
Q.113Easy
Which of the following is a biotic component of an ecosystem?
Answer: B
Decomposers are living organisms that break down dead matter, making them biotic components. Soil, water, and temperature are abiotic components.
Q.114Easy
What is the primary source of energy in most ecosystems?
Answer: C
Solar radiation captured by photosynthetic organisms is the primary energy source for almost all ecosystems on Earth.
Q.115Easy
Which type of succession occurs on a newly formed volcanic island?
Answer: B
Primary succession occurs on bare, newly exposed surfaces with no pre-existing soil or organisms, such as volcanic islands.
Q.116Easy
Which gas is primarily responsible for the greenhouse effect in the atmosphere?
Answer: C
CO₂ is the major anthropogenic greenhouse gas, comprising about 76% of total greenhouse gas emissions, contributing significantly to global warming.
Q.117Easy
What is the process by which plants release water vapor through their leaves?
Answer: B
Transpiration is the release of water vapor by plants through stomata in leaves. Evaporation refers to water bodies.
Q.118Easy
Which of the following is NOT a renewable resource?
Answer: C
Coal is a non-renewable fossil fuel formed over millions of years. Solar, wind, and geothermal are renewable resources.
Q.119Easy
In a pond ecosystem, phytoplankton occupy which trophic level?
Answer: B
Phytoplankton are autotrophic organisms that produce their own food through photosynthesis, making them primary producers in aquatic ecosystems.
Q.120Easy
The 10% law in ecology states that approximately what percentage of energy is transferred from one trophic level to the next?
Answer: C
The 10% law indicates that only about 10% of energy available at one trophic level is transferred to the next level, with the rest lost as heat and through metabolic processes.
