The name .Cnidaria. refers to

Options

A. cnidcytes - totipotent cells
B. cnidocytes-stinging cells
C. gastro - vascular cavity
D. alternation of generations

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Cnidaria":**
- The name "Cnidaria" is derived from a Latin word. To understand what it refers to, we need to break down the term.

2. **Identifying the Meaning of "Cnidaria":**
- The term "Cnidaria" is linked to "cnidocytes," which are specialized cells found in these organisms. These cells are responsible for the stinging mechanism.

3. **Exploring the Function of Cnidocytes:**
- Cnidocytes contain structures called nematocysts, which are stinging capsules that can inject toxins into prey or potential threats. This is a defining characteristic of the phylum Cnidaria.

4. **Examples of Cnidarians:**
- Organisms such as jellyfish, corals, and sea anemones belong to this phylum. They all possess cnidocytes, which is a key feature that distinguishes them.

5. **Eliminating Incorrect Options:**
- The other options provided (gastrovascular cavity and alternation of generations) do not define the term "Cnidaria." While Cnidarians may have a gastrovascular cavity and exhibit alternation of generations, these are not what the name specifically refers to.

6. **Conclusion:**
- Therefore, the correct answer to the question is that "Cnidaria" refers to "stinging cells" or "cnidocytes."

### Final Answer:
The name "Cnidaria" refers to stinging cells known as cnidocytes.

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