Connecting link between glycolysis and $TCA$ cycle is

During the conversion of pyruvic acid to acetyl $CoA$,pyruvic acid is .....

The common substrate used in the process of respiration is:

Which of the following reasons explain why plants do not have specialized respiratory organs?
$I-$ Each plant part takes care of its own gas exchange needs.
$II-$ There is very little transport of gases from one plant part to another.
$III-$ The rate of respiration in plants is much slower compared to animals.
$IV-$ Plants have a higher requirement for gas exchange.
$V-$ During photosynthesis,the plant's requirement for oxygen from the atmosphere increases.
$VI-$ In large,dense plants,gases can diffuse over long distances.
$VII-$ In plants,each living cell is located very close to the plant surface.

The complete combustion of glucose in respiration is represented by:

Which of the following is formed during respiration?