Tom' cat arranges the glass balls, in a particular 3D array, that two (I and II) continuous layer are not identical, but all (I and III) alternative layer are identical, this type of arrangement is known as:

Answer

To solve the question, we need to analyze the arrangement of the glass balls in Tom's cat's 3D array based on the given conditions.

### Step-by-Step Solution:

1. **Understanding the Layers**:
- We have two types of layers: Layer I and Layer II.
- The problem states that two continuous layers are not identical. This means that if Layer I is "A", then Layer II must be "B".

2. **Identifying Alternate Layers**:
- The problem also states that alternate layers are identical. This means that Layer III will be identical to Layer I (A), and Layer IV will be identical to Layer II (B).
- Therefore, the sequence of layers can be represented as:
- Layer I: A
- Layer II: B
- Layer III: A
- Layer IV: B

3. **Recognizing the Pattern**:
- From the arrangement, we can see a repeating pattern of layers: A, B, A, B.
- This indicates that every alternate layer is identical.

4. **Identifying the Type of Arrangement**:
- The arrangement of layers follows an "ABAB" pattern, which is characteristic of a specific type of packing in solids.
- This arrangement corresponds to the Hexagonal Close Packing (HCP) structure.

5. **Conclusion**:
- Therefore, the type of arrangement described in the question is known as **Hexagonal Close Packing (HCP)**.

### Final Answer:
The arrangement is known as **Hexagonal Close Packing (HCP)**.