Organism which can respire in the absence of $O_2$ is

What is the net number of $ATP$ molecules produced during lactic acid fermentation?

In which one of the following processes $CO_2$ is not released?

In the following flow chart, replace the symbols $a$, $b$, $c$ and $d$ with appropriate terms. Briefly explain the process and give any two applications of it.

The energy-releasing metabolic process in which substrate is oxidized without an external electron acceptor is called:

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?