Which of the following is a group of blue-green algae that acts as a biofertilizer?

$\cos ^2\left(\frac{\pi}{6}+\theta\right)-\sin ^2\left(\frac{\pi}{6}-\theta\right)$ is equal to

If the pairs of straight lines $x^2-2 p x y-y^2=0$ and $x^2-2 q x y-y^2=0$ are such that each pair bisects the angle between the other pair,then

$A$ plane electromagnetic wave of wave intensity $6 \, W/m^2$ strikes a small mirror of area $40 \, cm^2$,held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be:

The structure of the compound formed when nitrobenzene is reduced by lithium aluminium hydride $(LiAlH_4)$ is