Both centrioles in a centrosome lie .... ( i ) .... to each other and each of them contains..... ( ii ) ...... Peripheral fibril with .... ( iii ) .... arrangement of microtubules.

Options

A. (i) parallel (ii) triplet (ii) 9+0
B. (i) Perpendicular (ii) doublet (iii) 9+2
C. (i) parallel (ii) doublet (ii) 9+0
D. (i) Perpendicular (ii) triplet (iii) 9+0

Answer

To solve the question regarding the structure of centrioles in a centrosome, we can break it down into three parts based on the blanks provided:

### Step-by-Step Solution:

1. **Understanding the Orientation of Centrioles**:
- Centrioles are cylindrical structures found in the centrosome. In a typical centrosome, there are two centrioles.
- These two centrioles are arranged in a specific orientation relative to each other.
- The correct term to fill in the first blank is **"perpendicular"**. This means that the two centrioles are oriented at right angles (90 degrees) to each other.

2. **Identifying the Composition of Centrioles**:
- Each centriole is composed of microtubules, which are structural components made of tubulin proteins.
- The arrangement of these microtubules in each centriole is organized in a specific way.
- The correct term to fill in the second blank is **"triplet"**. This indicates that each centriole is made up of microtubules arranged in groups of three (triplets).

3. **Describing the Arrangement of Microtubules**:
- The arrangement of microtubules in centrioles can be characterized by a specific pattern.
- In centrioles, the arrangement is often described as **"9 + 0"**, which means there are nine triplets of microtubules arranged in a circle, with no central microtubules in the middle.

### Final Answer:
- (i) perpendicular
- (ii) triplet
- (iii) 9 + 0