Introduction:
Anaerobic respiration is a process by which cells obtain energy from the breakdown of food molecules in the absence of oxygen. It is an alternative to aerobic respiration, which occurs in the presence of oxygen. This process is commonly observed in certain microorganisms, as well as in muscle cells during intense exercise when oxygen supply is limited. In anaerobic respiration, food is broken down to release energy, and this statement (option A) is correct. Let's explore this further.

Explanation:
1. Anaerobic respiration:
Anaerobic respiration is a series of chemical reactions that occur in the absence of oxygen. It is an important metabolic process for organisms that live in environments with low or no oxygen availability. During anaerobic respiration, food molecules such as glucose are partially broken down to release energy. This energy is used by cells to perform various functions.

2. Absence of oxygen:
In anaerobic respiration, the breakdown of food occurs in the absence of oxygen. This is in contrast to aerobic respiration, where oxygen is required for the complete breakdown of food molecules. Without oxygen, the breakdown of food is incomplete, resulting in the formation of different byproducts depending on the specific organism and metabolic pathway involved.

3. Energy production:
Although anaerobic respiration does produce energy, it is generally less efficient compared to aerobic respiration. This is because aerobic respiration can fully oxidize glucose, resulting in the production of a larger amount of energy in the form of ATP (adenosine triphosphate). In anaerobic respiration, the breakdown of glucose stops at a certain intermediate stage, leading to the production of fewer ATP molecules.

4. Lactic acid and alcohol fermentation:
Two common types of anaerobic respiration are lactic acid fermentation and alcohol fermentation. Lactic acid fermentation occurs in certain bacteria and our muscle cells when there is a lack of oxygen. It results in the production of lactic acid as a byproduct. Alcohol fermentation, on the other hand, occurs in yeast and some bacteria, leading to the production of alcohol (ethanol) and carbon dioxide.

Conclusion:
In summary, anaerobic respiration is a process that occurs in the absence of oxygen. It involves the partial breakdown of food molecules to release energy. While it does produce energy, it is less efficient and generates smaller amounts of ATP compared to aerobic respiration. Anaerobic respiration can result in the production of different byproducts, such as lactic acid or alcohol, depending on the organism and metabolic pathway involved. Thus, the correct statement for anaerobic respiration is option A: "Food is broken down in the absence of oxygen to release energy."

Anaerobic respiration means food is broken down without the help of oxygen and aerobic respiration takes place with the help of oxygen so correct answer is C