During nodule formation in leguminous plants, an infection thread is produced carrying the __(i)__ into the __(ii)__ of the root, where they initiate the nodule formation in the __(iii)__ of the root. Fill up the blanks by choosing the correct option.

Options

A. `{:("(i)","(ii)","(iii)"),("Cyanobacteria","pericycle","cortex"):}`
B. `{:("(i)","(ii)","(iii)"),("bacteria","cortex","cortex"):}`
C. `{:("(i)","(ii)","(iii)"),("Cyanobacteria","cortex","pericycle"):}`
D. `{:("(i)","(ii)","(iii)"),("bacteria","pericycle","pericycle"):}`

Answer

To answer the question regarding nodule formation in leguminous plants, we need to fill in the blanks based on the process described in the video transcript. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understanding Nodule Formation**:
- Leguminous plants form nodules in a symbiotic relationship with nitrogen-fixing bacteria, primarily Rhizobium.

2. **Infection Thread Production**:
- During nodule formation, an infection thread is produced. This thread is a structure that allows the bacteria to enter the plant root.

3. **Identifying the First Blank**:
- The infection thread carries the **bacteria** into the root. Thus, the first blank is filled with **"bacteria"**.

4. **Identifying the Second Blank**:
- The bacteria travel through the infection thread into the **cortex** of the root. Therefore, the second blank is filled with **"cortex"**.

5. **Identifying the Third Blank**:
- The bacteria initiate nodule formation in the **cortex** of the root, where they convert into bacteroids and start fixing nitrogen. Thus, the third blank is also filled with **"cortex"**.

### Final Answer:
The completed sentence is:
"During nodule formation in leguminous plants, an infection thread is produced carrying the **(i) bacteria** into the **(ii) cortex** of the root, where they initiate the nodule formation in the **(iii) cortex** of the root."