Which of the following is an incorrect pair?

For many biochemical reactions,$H^+$ and $OH^-$ ions are obtained from which of the following?

How many covalent bonds are present in the water molecules shown in the given figure?

Categorize the following processes as Anabolic or Catabolic:
$I -$ Protein synthesis,
$II -$ Lactic acid fermentation,
$III -$ Aerobic respiration,
$IV -$ Alcoholic fermentation,
$V -$ Synthesis of cholesterol from acetic acid,
$VI -$ Photosynthesis,
$VII -$ Digestion,
Identify the Anabolic and Catabolic processes respectively.

Which of the following minerals is present in Vitamin $B_{12}$?

Match the names of items listed under column $I$ with the items given under column $II$; choose the answer which gives the correct combination of the alphabets of the two columns.

Column $-I$	Column $-II$
$(A)$ Ketone	$(p)$ Has $5$ carbon sugar,a phosphate group and a nitrogenous base
$(B)$ Fatty acid	$(q)$ Has long chain of carbon and hydrogen atoms and a carboxyl group at one end
$(C)$ Aldehyde	$(r)$ Has a carbonyl group at the end of the carbon chain
$(D)$ Nucleotide	$(s)$ Has a carbonyl group within the carbon chain