Identify the fibrous protein from the following.

Which pair of oxyacids of phosphorus contains $P-H$ bonds?

Which substance is used as a smoke screen in warfare?

In an alkaline medium,$H_2O_2$ exists as ........

Endosperm is consumed by the developing embryo in the seed of

$A$ particle is moving on a circular path of radius $r$ with uniform speed $v$. The change in velocity when the particle moves from $P$ to $Q$ is $(\angle POQ = 40^\circ)$.