A biologist studied population of rats in a barn. He found that average natality was 250 , average m

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11.Organisms and Populations

medium

A biologist studied the population of rats in a barn. He found that the average natality was $250$, average mortality $240$, immigration $20$ and emigration $30$. The net increase in population is

$5$

zero

$10$

$15$

(NEET-2013)

Solution

(b) : Natality and immigration positively contribute to the population growth while mortality and emigration are negative factors. In the given question,The net increase in population is natality + immigration = $250 + 20 = 270 $ The net decrease in population is mortality + emigration = $240 + 30 = 270$ Thus, net increase in population = $270 -270 = 0$

Standard 12

Biology