Fermentation is:

Which type of respiration occurs in the muscle cells of animals during vigorous exercise?

Identify the products marked by $(i)$ and $(ii)$ in the following pathway:
$3$-phosphoglyceric acid $\rightarrow$ $(i)$ $\rightarrow$ Pyruvate $\rightarrow$ $(ii)$ (with $NADH + H^+$ being converted to $NAD^+$)

Radha was running on a treadmill at a great speed for $15$ minutes continuously. She stopped the treadmill and abruptly came out. For the next few minutes,she was breathing heavily/fast. Answer the following questions.
$(a)$ What happened to her muscles when she did strenuous exercise?
$(b)$ How did her breathing rate change?

Which of the following processes may be toxic to plants?

Alcoholic fermentation occurs in the presence of which enzyme?