The first transgenic plant was tobacco. It contains a resistance gene against which of the following?

Which of the following compounds has the lowest melting point?

Which of the following statements are true about acceleration due to gravity $(g)$ of the earth (where $r$ is distance from the centre of the earth and $R$ is the radius of the earth)?
$(a)$ $g$ decreases in moving away from the centre,if $r > R$.
$(b)$ $g$ decreases in moving away from the centre,if $r < R$.
$(c)$ $g$ is zero at the centre of the earth.
$(d)$ $g$ at the equator decreases,if the earth stops rotating about its axis.

The formation of which of the following polymers involves a hydrolysis reaction?

$\int \frac{dx}{\sqrt{x-x^2}}$ is equal to

Which type of circulatory system is shown in the given figure?