Which of the following transfers electrons in the $E.T.S.$ (Electron Transport System)?

The mobile electron carrier in the $ETS$ of the mitochondrial membrane is:

During which stage in the complete oxidation of glucose are the greatest number of $ATP$ molecules formed from $ADP$?

The ultimate electron acceptor in $ETS$ of aerobic respiration is . . . . . . .

In which of the following are iron-porphyrin protein complexes found?

Given below are two statements.
$Statement-I$: During aerobic respiration, $ETS$ releases energy in a stepwise manner to prevent damage to cells.
$Statement-II$: During aerobic respiration, $ETS$ provides water molecules.
In the light of the above statements, choose the correct answer from the options given below.