The correct answer is: B. Two centriole
Centrioles are small, cylindrical organelles found in animal cells. They are located near the nucleus and are involved in cell division. Centrioles are made up of nine triplets of microtubules, which are long, thin protein filaments. The microtubules are arranged in a ring around the centriole, and they help to organize the mitotic spindle during cell division.
Centrioles are also involved in the formation of cilia and flagella. Cilia are short, hair-like projections that are used for movement, while flagella are longer, whip-like projections that are used for propulsion.
In some microorganisms and lower plants, centrioles are absent. In these organisms, cell division is mediated by other structures, such as the spindle apparatus.
Here is a brief explanation of each option:
- A. One centriole. This is incorrect because centrioles are always found in pairs.
- B. Two centriole. This is the correct answer because centrioles are always found in pairs.
- C. Three centriole. This is incorrect because centrioles are always found in pairs.
- D. Four centriole. This is incorrect because centrioles are always found in pairs.