Read the given statement and select the option that correctly identifies X and Y.
In a glycogen molecule, successive glucose units are joined together by X and branches are linked together by Y.

Options

A. `{:(" X",," Y"),("1,4"-alpha- "glycosidic bonds",,"1,4-" alpha-"glycosidic acid"):}`
B. `{:(" X",," Y"),("1,4"-alpha- "glycosidic bonds",,"1,6-" alpha-"glycosidic bonds"):}`
C. `{:(" X",," Y"),("1,6"-alpha- "glycosidic acid",,"1,4-" alpha-"glycosidic acid"):}`
D. `{:(" X",," Y"),("1,6"-alpha- "glycosidic acids",,"1,6-" alpha-"glycosidic acid"):}`

Answer

To solve the question regarding the structure of glycogen and the bonds that connect its glucose units, we can break it down into the following steps:

### Step-by-Step Solution

1. **Understanding Glycogen**:
- Glycogen is a polysaccharide that serves as a form of energy storage in animals. It is composed of many glucose units linked together.

2. **Identifying the Bonds**:
- In glycogen, the glucose units are connected in a linear fashion by specific types of glycosidic bonds.

3. **Linear Connections**:
- The linear connections between successive glucose units are formed by **alpha 1 to 4 glycosidic bonds**. This means that the bond is formed between the first carbon of one glucose molecule and the fourth carbon of the next glucose molecule.

4. **Branching Connections**:
- Glycogen also has branching points. These branches are formed by **alpha 1 to 6 glycosidic bonds**. This bond connects the first carbon of one glucose molecule to the sixth carbon of another glucose molecule, allowing for the branching structure.

5. **Conclusion**:
- Therefore, in the context of the question, X (the bond connecting successive glucose units) is **alpha 1 to 4 glycosidic bond**, and Y (the bond linking branches) is **alpha 1 to 6 glycosidic bond**.

### Final Answer:
- X = alpha 1 to 4 glycosidic bond
- Y = alpha 1 to 6 glycosidic bond