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Biology · 2025 · 1 mark
CBSE 2025 · Region 7 · Set 1 · Q10
A biologist studied the population of rats in a granary. He found the average natality was 280, average mortality was 200, immigration was 40 and…
A biologist studied the population of rats in a granary. He found the average natality was $\displaystyle 280$ , average mortality was $\displaystyle 200$ , immigration was $\displaystyle 40$ and emigration was $\displaystyle 50$ . The net increase in population is :
Official answer
(B)
$\displaystyle 70$
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CBSE Class 12 Biology past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.