Which of the following is a polyamide?

Which of the following oxides is the least acidic?

$A$ point moves in the $xy$-plane such that the sum of its distances from two mutually perpendicular lines is always equal to $5$ units. The area (in sq units) enclosed by the locus of the point is

Which stage is indicated by the given figure?

If the pair of lines represented by $3 x^2 - 5 x y + P y^2 = 0$ and $6 x^2 - x y - 5 y^2 = 0$ have one line in common,then the sum of all possible values of $P$ is

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