On the basis of the passage given above, the following assumptions have been made:
- 1.BPA may alter embryonic development in vivo.
- 2.Biochemical and cell-based assays are useful in finding out treatments for pollution-induced diseases.
- 3.Embryonic stem cells could serve as a model to evaluate the physiological effects of environmental pollutants.
Which of the above assumptions are valid?
Answer & explanation
Answer: (c) 1 and 3 only
The researchers used mouse embryonic stem cells to detect and measure BPA's toxicity to germ layers and neural progenitor cells. So stem cells can model pollutant effects (3), and BPA may disturb development in a living embryo (1); the passage says nothing about finding treatments (2).
- ✓ 1. BPA disturbed 'the proper specification of primary germ layers' in embryonic cells and is known to cause 'developmental abnormalities in humans' — so it may alter development in a living body.
- ✗ 2. The assays were used to examine gene expression and measure toxicity, not to find treatments for any disease.
- ✓ 3. The whole study used stem cells 'to gauge the neurotoxic effects of the environmental pollutant' — exactly the role of a model system.
Remember · Separate what a method was shown to do (detect, measure) from what it was never said to do (treat, cure).
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·