Question

Which of the following respires only anaerobically?

• A. Cockroaches
• B. Yeast
• C. Fungi
• D. All bacteria

Answer 1

The correct option is B

Yeast

The correct option is B.

Explanation of the correct option:

1. Obligate anaerobes are organisms that cannot survive in the presence of oxygen.
2. Yeast, also known as Saccharomyces cerevisiae is an example.
3. It is a saprotrophic fungus.
4. In the absence of oxygen, it converts the glucose in the food to ethanol and carbon dioxide by a process called fermentation.

Explanation of the incorrect options:

Option A:

1. The cockroach is an insect that cannot survive in the absence of oxygen.
2. It needs oxygen to produce energy from the food it consumes.

Option C:

1. Fungi can live in both aerobic and anaerobic environments.
2. Fusarium, Penicillium, and other aerobic fungi are examples.

Option D:

1. Bacteria can be both aerobic and anaerobic.
2. Anaerobic bacteria are present in the gut.
3. Aerobic bacteria include Pseudomonas, Bacillus, and others.

Final answer: Yeast respires only anaerobically.