Alcoholic fermentation occurs in the presence of which enzyme?

Anaerobic respiration takes place in the

The conversion of glucose into lactic acid is a process known as:

Which of the following is the most common organism that can respire even in the absence of $O_2$?

What is the total net gain of energy during anaerobic respiration?

Given below are two statements.
$Statement-I$ - Skeletal muscles usually derive energy by anaerobic respiration.
$Statement-II$ - After vigorous exercise,lactic acid accumulates in muscle fibres,leading to muscle fatigue.
In the light of the above statements,choose the most appropriate answer from the options given below: