Entamoeba histolytica differs from Amoeba with absence of

Options

A. Nucleus
B. Contractile vacuole
C. Endosome (Karyosome)
D. Food vacuole

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the differences between Entamoeba histolytica and Amoeba, specifically focusing on what is absent in Entamoeba histolytica but present in Amoeba.

2. **Analyzing the Options**:
- **Option 1: Nucleus**: Both Entamoeba histolytica and Amoeba possess a nucleus. Therefore, this option is incorrect.
- **Option 2: Contractile Vacuole**: The contractile vacuole is responsible for regulating water content in freshwater protozoa. Amoeba, which lives in freshwater, has a contractile vacuole to eliminate excess water. In contrast, Entamoeba histolytica lives in an isotonic environment (like the human intestine), where osmosis does not occur, and thus it does not require a contractile vacuole. This makes this option correct.
- **Option 3: Endosome/Karyosome**: The endosome (or karyosome) is present in both organisms as it is part of the nuclear structure. Thus, this option is incorrect.
- **Option 4: Food Vacuole**: Both Entamoeba histolytica and Amoeba have food vacuoles, which are used for storing food. Therefore, this option is also incorrect.

3. **Conclusion**: After analyzing all the options, the correct answer is that Entamoeba histolytica differs from Amoeba in the absence of the **contractile vacuole**.

### Final Answer:
**Entamoeba histolytica differs from Amoeba with the absence of the contractile vacuole.**

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