What is the stored food material in fungi?

$A$ system is provided with $50 \ J$ of heat and the work done on the system is $10 \ J$. What is the change in internal energy of the system in joules?

Which of the following fluorides does not exist?

The correct order of reactivity for reactions involving the cleavage of the $C-X$ bond in the following compounds is:

The value of $\left|\begin{array}{lll}1990 & 1991 & 1992 \\ 1991 & 1992 & 1993 \\ 1992 & 1993 & 1994\end{array}\right|$ is

If $\cos (x-y), \cos x, \cos (x+y)$ are three distinct numbers which are in harmonic progression and $\cos x \neq \cos y$,then $1+\cos y$ is equal to