Question

Which of the following is not a unicellular organism?

• A. Amoeba
• B. Yak
• C. Yeast
• D. Rhizobium

Answer 1

The correct option is B

Yak

The correct option is B.

Explanation of correct option:

1. A single-celled organism also called a unicellular organism is an organism formed of a single cell. On the other hand, a multicellular organism is formed of multiple cells.
2. Yaks are a kind of multicellular organism.
3. It is a long-haired domesticated cattle, which can be seen all through the Indian subcontinent’s Himalayan region.

Explanation of incorrect options:

Option A:

1. Amoeba is a unicellular organism, as it comprises a single cell.
2. All the life processes, like feeding, reproduction, excretion, and digestion occur in a single cell in amoeba.

Option C:

1. Yeast is a eukaryotic, unicellular microbe, which comes under the kingdom fungi.
2. Yeasts have an application in the alcoholic and beverage industries.

Option D:

1. Rhizobium is a bacterial genus, which is associated with the formation of root nodules in plants.
2. It is a unicellular bacterial species.
3. These bacteria prevail in a symbiotic association with the legumes.

Final answer: Yak is not a unicellular organism.