Which of the following structures contains its own $DNA$?

If in a $\triangle ABC$,$r_1 < r_2 < r_3$,then:

This is the only type of pollination which during pollination brings genetically different types of pollen grains to the stigma.

The coefficient of apparent expansion of a liquid when determined using two different vessels $A$ and $B$ are $\gamma_1$ and $\gamma_2$ respectively. If the coefficient of linear expansion of the vessel $A$ is $\alpha$,then find the coefficient of linear expansion of vessel $B$.

Who is affected by the consumption of drugs during pregnancy?

When an object of height $12 \ cm$ is placed at a distance from a convex lens, an image of height $18 \ cm$ is formed on a screen. Without changing the positions of the object and the screen, if the lens is moved towards the screen, another clear image is formed on the screen. The height of this image is (in $cm$)