Name the cell organelle in which the breakdown of pyruvate to give carbon dioxide,water,and energy takes place.

When a sportsman runs,he gets muscle cramps. Why?

If a plant is releasing carbon dioxide and taking in oxygen during the day,does it mean that there is no photosynthesis occurring? Justify your answer.

How are the alveoli designed to maximise the exchange of gases?

What are the common features of the respiratory organs in aquatic and terrestrial animals?

Which of the following statement$(s)$ is (are) correct?
$(i)$ Pyruvate can be converted into ethanol and carbon dioxide by yeast.
$(ii)$ Fermentation takes place in aerobic bacteria.
$(iii)$ Fermentation takes place in mitochondria.
$(iv)$ Fermentation is a form of anaerobic respiration.