Chromatophores take part in

$X$ and $Y$ are two metals. When burnt in air,$X$ forms only oxide while $Y$ forms oxide and nitride. The metals $X$ and $Y$ may be

In ruby laser,the stimulated emission is due to transition from

The area (in sq units) of the quadrilateral formed by two pairs of lines $\lambda^2 x^2 - m^2 y^2 - n(\lambda x + m y) = 0$ and $\lambda^2 x^2 - m^2 y^2 + n(\lambda x + m y) = 0$ is:

In transgenics,the expression of a transgene in the target tissue is determined by:

During which phase of the cell cycle are the proteins and microtubules required for mitosis synthesized?