NEET 2016 Phase 2 question paper with solutions

1. Recall what osteoporosis is.

Osteoporosis is a reduction in bone mineral density, which makes bones brittle and prone to fracture.

2. Recall who is commonly affected.

Generalised osteoporosis is common in the elderly, and especially in women after menopause.

3. Understand the link to estrogen.

After menopause, estrogen levels in blood plasma drop significantly. Estrogen normally helps regulate osteoclasts, the cells responsible for building new bone.

4. Connect low estrogen to bone loss.

When estrogen levels drop, fewer osteoclasts are produced, which results in osteoporosis.

5. Eliminate the other options.

An immune disorder affecting the neuromuscular junction describes myasthenia gravis, and accumulation of uric acid causing joint inflammation describes gout — neither is the cause of osteoporosis.

Hence, the answer is Option C (decreased level of estrogen).

1. Define BOD clearly: Biochemical Oxygen Demand (BOD) measures the amount of oxygen consumed by aerobic decomposer microbes while they break down biodegradable organic material present in water.

2. Understand what BOD actually indicates: Since BOD relies on microbial decomposition, it is a reliable indicator of pollution only when the pollutant itself is biodegradable (i.e., microbes can break it down).

3. Evaluate petroleum industry effluents: Petroleum-based pollutants (like oils and hydrocarbons) are generally not easily degraded by decomposer microbes. Since microbes can't break it down effectively, it won't significantly raise the BOD value, even though the water is polluted.

4. Evaluate the other sources: Effluents from the sugar industry, dairy industry, and domestic sewage all contain large amounts of biodegradable organic matter, which decomposers readily break down — making BOD a reliable and accurate pollution indicator for these sources.

5. Conclude: Since BOD fails to properly reflect pollution levels from non-biodegradable petroleum waste, it is not a good index for effluents from the petroleum industry.

Hence, the answer is A. petroleum industry.

1. Recall the meaning of radial symmetry (actinomorphic).

A flower shows radial symmetry when it can be divided into two equal halves by any vertical plane passing through its centre.

2. Apply this to Brassica.

Brassica (mustard) flowers have petals arranged uniformly around the centre, allowing division into equal halves along any plane, so they are actinomorphic (radially symmetric).

3. Check the remaining options.

Trifolium, Pisum (pea), and Cassia all belong to families with irregularly shaped flowers that can be divided equally only along one specific plane, making them zygomorphic (bilaterally symmetric), not radially symmetric.

Hence, the answer is option A: Brassica.