If $10$ individuals in a laboratory population of $50$ fruit flies die during a week, then the death rate during this period is $= ........$ individuals per fruit fly per week.

What is true about the isolated small tribal populations?

Which of the following is $NOT$ a primary factor affecting population density?

$A$ biologist studied a rat population at the time of birth. He observed that the estimated births were $250$, estimated deaths were $240$, $20$ rats immigrated into the population, and $30$ rats emigrated from the population. What was the net increase in the population?

Which of the following countries has the highest population density?

Choose the wrong statement.