[A]: The germination of lettuce seeds is stimulated by red light and inhibited by infra- red light.
[R]: Red light converts pr to active pfr form.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To solve the question regarding the germination of lettuce seeds and the role of light, we can break it down into clear steps:

### Step 1: Understand the Assertion (A)
The assertion states that "The germination of lettuce seeds is stimulated by red light and inhibited by infrared light."

**Explanation**: This means that when lettuce seeds are exposed to red light, they are more likely to germinate, while exposure to infrared light prevents them from germinating.

**Hint**: Think about how different wavelengths of light can affect plant processes.

### Step 2: Understand the Reason (R)
The reason states that "Red light converts pr to active pfr form."

**Explanation**: This refers to the phytochrome system in plants. Phytochromes are light-sensitive proteins that exist in two forms: Pr (inactive form) and Pfr (active form). Red light is responsible for converting Pr to Pfr, which is essential for triggering various physiological responses, including seed germination.

**Hint**: Consider how light influences biochemical pathways in plants.

### Step 3: Evaluate the Truth of A and R
Now, we need to determine if both statements A and R are true.

- **Is A true?** Yes, it is true that red light stimulates germination and infrared light inhibits it.
- **Is R true?** Yes, it is true that red light converts Pr to Pfr, which is crucial for the germination process.

**Hint**: Look for scientific evidence that supports the effects of light on seed germination.

### Step 4: Determine if R is the Correct Explanation for A
Next, we need to assess whether R provides a correct explanation for A.

- Since R explains the mechanism by which red light stimulates germination (by converting Pr to Pfr), it directly supports the assertion made in A.

**Hint**: Think about whether understanding the mechanism (R) helps clarify the observation (A).

### Conclusion
Both statements A and R are true, and R is the correct explanation for A.

**Final Answer**: Both A and R are true, and R is the correct explanation of A.