Refer to the given reactions.
(i) Adenine `+X to `Adenosine
(ii) Adenosine `+Y to` Adenylic acid
What does X and Y represent here ?

Options

A. a) `{:(" X",," Y"),("Phosphate",,"Sugar molecule"):}`
B. b) `{:(" X",," Y"),("Sugar molecule",,"Phosphate group"):}`
C. c) `{:(" X",," Y"),("Sugar molecule",,"Nitrogenous base"):}`
D. d) `{:(" X",," Y"),("Nitrogenous base",,"Sugar molecule"):}`

Answer

To solve the problem, we need to analyze the given reactions step by step.

### Step 1: Understanding the First Reaction
The first reaction is:
- **Adenine + X → Adenosine**

In this reaction, we are starting with adenine, which is a nitrogenous base. Adenosine is formed when adenine is combined with a sugar molecule. Therefore, in this context, **X represents a sugar molecule**.

### Step 2: Understanding the Second Reaction
The second reaction is:
- **Adenosine + Y → Adenylic Acid**

Here, we start with adenosine, which is a nucleoside (a nitrogenous base attached to a sugar). Adenylic acid is a nucleotide, which consists of a nitrogenous base, a sugar, and a phosphate group. To form adenylic acid from adenosine, a phosphate group must be added. Therefore, **Y represents a phosphate group**.

### Conclusion
From the analysis of both reactions, we can conclude:
- **X is a sugar molecule**
- **Y is a phosphate group**

### Final Answer
- X = Sugar molecule
- Y = Phosphate group