AIPMT 2015 Cancelled Paper question paper with solutions

1. Checking option A: Cyclostomes do have a jawless, sucking circular mouth and lack scales, but they actually possess unpaired, not paired, fin-like appendages, making this combination inaccurate. So, option A is incorrect.

2. Checking option B: Birds do have feathers and wings, but their skin is dry, not moist and glandular (except for a single oil gland near the tail base), so this description doesn't fully match. So, option B is incorrect.

3. Checking option C: Mammals generally have mammary glands, hair, and pinnae, but aquatic mammals (like whales) and egg-laying mammals (like the platypus) often lack external pinnae, so this isn't true without exception. So, option C is incorrect.

4. Checking option D: Class Chondrichthyes (like sharks and rays) consistently show a ventrally placed mouth, gills without an operculum covering, tough placoid scales on the skin, and a notochord that persists throughout life — all true without known exception in this class. So, option D is correct.

5. Conclusion: Only option D holds true universally for its group. Hence, the answer is option D.

1. Define BOD precisely: Biochemical Oxygen Demand (BOD) is defined as the amount of oxygen required by microbes to decompose a given mass of organic matter present in water.

2. Understand what a high BOD value means: A high BOD value means that microbes are consuming a large amount of oxygen while breaking down organic material — this happens specifically when the amount of organic matter available for microbial decomposition is high.

3. Connect BOD to pollution level: Since more organic matter (like sewage) typically means more pollution, a higher BOD is generally associated with more polluted water — but the value itself directly measures microbial oxygen consumption, not pollution as a category.

4. Choose the most precise option: While option A (highly polluted) is a common association, the definition of BOD is most precisely described by option B — it directly reflects the amount of organic matter being consumed by microbes.

5. Rule out the remaining options: 'Water is pure' and 'water is less polluted' both contradict the meaning of a high BOD value, since more oxygen consumption by microbes indicates more organic pollutants, not fewer.

Hence, the answer is B. consumption of organic matter in the water is higher by the microbes.

1. Recall the basic structure of a chloroplast. A chloroplast is bound by an envelope of two membranes and filled with a fluid matrix called the stroma.

2. Identify the flattened sacs within the stroma. Inside the stroma, closed, flattened, ovoid sacs called thylakoids are present.

3. Identify what forms when thylakoids stack together. When these thylakoids are stacked closely together in piles, they form structures called grana.

4. Eliminate the other options. Stroma lamellae are the thin tubules connecting different grana (not the stack itself), and cristae are folds found in mitochondria, not chloroplasts.

Hence, the answer is D. Grana.