Question
NEET 2022 (paraphrased): Regarding organisms and populations, which of the following statements is correct? (a) exponential growth refers to max population an environment can support (b) carrying capacity K is characterised by dN/dt = rN, unlimited resources (c) mutualism — both species benefit (lichen = fungus + alga) (d) commensalism has no role in organisms and populations
Solution — Step by Step
This option swaps the definitions. exponential growth is actually dN/dt = rN, unlimited resources, not what (a) claims. So (a) is out.
Similarly, carrying capacity K means max population an environment can support. Option (b) is mismatched. Out.
This one reads correctly: mutualism — both species benefit (lichen = fungus + alga). Match with NCERT wording confirms it.
commensalism — one benefits, other unaffected (orchid on tree) — plays a real role in organisms and populations, so option (d) is factually wrong.
Correct answer: (c) mutualism — both species benefit (lichen = fungus + alga).
Why This Works
NEET PYQs on organisms and populations rely on definition swapping. The examiner takes two correct facts and pairs them with the wrong terms. If you know each fact cold, the MCQ dissolves in 20 seconds.
Alternative Method
For definition-swap MCQs, don’t read all four options first. Read option (a), decide true/false, then (b), and so on. This prevents confusion between similar-looking options.
NEET reuses the same fact set every 2–3 years with different distractors. Master the four NCERT facts on organisms and populations listed here and you’ll handle almost any MCQ on this chapter.
Common Mistake
Students second-guess themselves when they see a familiar option listed as “wrong” in the stem. Trust the elimination — if you know the definition, stick with it.
Keep a one-page sheet of definitions for every NEET chapter. Revise only that sheet in the last 48 hours before the exam.