What is the bond length between $H$ and $O$ atoms in a water molecule?

The structural formula of $C_5H_{10}O_5$ is given. Select the correct group for the position marked '$X$' from the given options.

Bond found in cellulose

Which monosaccharide does not have the ratio of $H$ and $O$ atoms as $2:1$?

Match the following columns:

Column-$I$	Column-$II$
$P$. Chitin	$I$. $\alpha$-glucose
$Q$. Starch,Glycogen	$II$. $\beta$-glucose
$R$. Cellulose	$III$. $N$-acetyl glucosamine
$S$. Inulin	$IV$. Fructose

Which functional group is present in aldose sugars?