A : Bt toxin are protein crystals containing insecticidal protein
R : B. thuringiensis forms these protein crystals throughout continuously during their growth period.

Options

A. If both Asserition and Reason are true but the reason is the correct explaintion of the assertion.
B. If both Assertion and Reason are true buth the reason is not the correct explaination of the assertion
C. If Assertion and Reason in false
D. If both Assertion and Reason are false

Answer

To analyze the given statements about Bt toxin and Bacillus thuringiensis (B. thuringiensis), we will break down the assertion (A) and the reason (R) step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Bt toxin are protein crystals containing insecticidal protein."
- This is true. Bt toxin refers to the insecticidal proteins produced by Bacillus thuringiensis, which are indeed found in the form of protein crystals.

2. **Understanding the Reason (R)**:
- The reason states that "B. thuringiensis forms these protein crystals throughout continuously during their growth period."
- This statement is false. B. thuringiensis does not produce Bt toxin continuously throughout its growth period. Instead, it produces these protein crystals during a specific phase of its life cycle known as sporulation.

3. **Evaluating the Relationship**:
- Since the assertion (A) is true but the reason (R) is false, we conclude that the reason does not correctly explain the assertion.

4. **Final Conclusion**:
- The assertion is correct, while the reason is incorrect. Therefore, the correct answer is that A is true, and R is false.