What is the significance of respiration in living organisms?

$ATP$ formation occurs through which of the following?

Which of the following processes involves the loss of two protons and two electrons?

Match the following columns:

Column-$I$	Column-$II$
$P$. Aerobic respiration	$I$. Yeast
$Q$. Lactic acid fermentation	$II$. Some bacteria and animal muscles
$R$. Alcoholic fermentation	$III$. Human leukocytes

Read the following statements and choose the set of correct statements :
$(A)$ In fermentation, the reducing agent is $NADH + H^+$.
$(B)$ There are three major ways in which different cells handle pyruvic acid produced by glycolysis.
$(C)$ The complete oxidation of pyruvate occurs by the stepwise removal of all the hydrogen atoms, leaving three molecules of $CO_2$.
$(D)$ The $NADH$ synthesised in glycolysis is transferred into the mitochondria and undergoes oxidative phosphorylation.
$(E)$ Complex-$IV$ of $ETS$ refers to cytochrome $c$ oxidase complex.
Choose the most appropriate answer from the options given below :

In the hexose monophosphate shunt ($HMP$ shunt),the number of $CO_2$ molecules evolved is: