What is the number of covalent bonds and hydrogen bonds in a single molecule of water,respectively?

Energy released by the hydrolysis of one molecule of $ATP$ is (in $kcal$)

The energy available for the work of a biological system is known as.....

Match the following columns:

Column-$I$	Column-$II$
$1$. Oleate	$a$. Triose sugar
$2$. Trihydroxy alcohol	$b$. Unsaturated fatty acid
$3$. Glyceraldehyde	$c$. Subcutaneous fat layer
$4$. Amylopectin	$d$. Glycerol
$5$. Ergosterol	$e$. Branched chain of glucose units

Which of the following plays a significant role in energy exchange?

The provided image shows chemical structures related to resonance and electronic effects. Identify the correct relationship or description for these structures.