Which type of population is more efficient in all types of work?

Choose the correct option for $P$ and $Q$ in the given diagram representing population density $(N)$:

Which one of the following population attributes contributes to an increase in population density?

Which of the following attributes can be applied to an individual organism but not to a population?

Which of the following is the most sparsely populated state of India?

$(a)$ Label the three tiers $1, 2, 3$ given in the above age pyramid.
$(b)$ What type of population growth is represented by the above age pyramid?