What is the stored food (nutrient) in algae?

$(x^2+y^2) dy = xy dx$. If $y(x_0) = e$ and $y(1) = 1$,then the value of $x_0$ is equal to

Statement$-1$ : Toluene is more reactive than benzene in chlorination.
Statement$-2$ : During the nitration of Toluene $\stackrel{\oplus}{ N } O _2$ acts as electrophile.

The halide of a metal $MX$ crystallizes in a $ccp$ structure ($NaCl$ type). If all the atoms situated on one of the tetrad axes are removed,what will be the simplest molecular formula of the halide?

When $10 \ g$ of methane is completely burnt in oxygen,the heat evolved is $560 \ kJ$. What is the heat of combustion (in $kJ \ mol^{-1}$) of methane?

Which of the following is an essential amino acid?