During the first meiotic division,the exchange of genetic material between the chromatids of homologous chromosomes occurs. What is this process called?

Which of the following molecules has the highest dipole moment?

If $x + by + c = 0$ is a normal to the parabola $y^2 = 12x$,then the complete set of all values of $c$ is

Which of the following has the highest density?

If the direction cosines of two lines are given by $l+m+n=0$ and $l^2-5m^2+n^2=0$,then the angle between them is

Three identical square plates rotate about the axes shown in the figure in such a way that their kinetic energies are equal. Each of the rotation axes passes through the centre of the square. Then the ratio of angular speeds $\omega _1 : \omega _2 : \omega _3$ is