Box like calcareous test occurs in

Options

A. Sea Lily
B. Sea Star
C. Sand Dollar
D. Sea Cucumber.

Answer

To solve the question "Box like calcareous test occurs in," we need to analyze the options provided and understand the characteristics of the organisms mentioned.

### Step-by-Step Solution:

1. **Understanding the Term "Calcareous Test":**
- A calcareous test refers to a shell-like structure made of calcium carbonate. In echinoderms, this structure is often referred to as a test or skeleton that provides support and protection.

2. **Identifying Echinoderms:**
- All the options provided (sea lily, sea star, sand dollar, and sea cucumber) belong to the phylum Echinodermata, which is known for having a calcareous endoskeleton.

3. **Analyzing Each Option:**
- **Sea Lily (Feather Star):**
- Sea lilies have a star-shaped structure and do not possess a box-like test. Their structure is more branched and feather-like.
- **Sea Star (Starfish):**
- Sea stars have a radial symmetry and their structure is not box-like; they have arms extending from a central disc.
- **Sand Dollar:**
- Sand dollars are a type of flat sea urchin and when they die, they leave behind a flat, disc-shaped, box-like calcareous test. This matches the description given in the question.
- **Sea Cucumber:**
- Sea cucumbers have a cylindrical shape and when they die, they leave a cylindrical test, which does not fit the box-like description.

4. **Conclusion:**
- After analyzing all the options, the organism that leaves a box-like calcareous test is the **Sand Dollar**.

### Final Answer:
- The correct answer is **Sand Dollar**.

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