In almost all Indian metropolitan cities like Delhi,the major atmospheric pollutant$(s)$ is/are:

Which one of the following is the most widely accepted method of contraception in India,at present?

The solution of the differential equation $\frac{dy}{dx} = \frac{xy+y}{xy+x}$ is

Which of the following taxonomic categories is being described by the given statements $(i-iii)$?
$(i)$ It is the basic unit of classification.
$(ii)$ It is defined as the group of individuals which resemble in their morphological and reproductive characters and interbreed among themselves and produce fertile offsprings.
$(iii)$ Human beings belong to the species sapiens which is grouped in the genus Homo.

Which of the following pairs are isoelectronic and isostructural? $NO_3^-, CO_3^{2-}, ClO_3^-, SO_3$

Calculate the $pOH$ of a solution at $25\,^{\circ}C$ that contains $1 \times 10^{-10} \, M$ of hydronium ions,i.e.,$H_3O^{+}$.