Which of the following types of age pyramids reflects a stable population growth?

Read the following statements and select the correct option with respect to population attributes:
$(a)$ Population density is necessarily measured in numbers.
$(b)$ Tiger census is often based on pug marks and fecal pellets.
$(c)$ Biomass is not a meaningful measure to know population size.
$(d)$ Size of a population for any species is not a static parameter.

Maximum survival and reproductive capacity shown by a population under optimal environmental conditions is called

Sex ratio in a species indicates the numerical relation between the number of

Which of the following factors contribute to an increase in population density?

If birth rate is $100,$ death rate is $10,$ and the number of individuals in the population group is $1000,$ then what will be the percentage of natural growth rate (in $, \%$)?