There are two types of organisms know to us based on cell types : prokaryote and eukaryote . Among the given features , select the one that distinguishes prokaryotic organisms from eukaryotic organisms .

Options

A. Prokaryotes are unicellular , while all eukaryotes are multicellular .
B. Prokaryotes are aquatic , while eukaryotes are terrestrial .
C. Prokaryotes are structurally less complex than eukaryotes are .
D. Prokaryotes lack cell membrane , while eukaryotes .do not .

Answer

To distinguish prokaryotic organisms from eukaryotic organisms, we need to analyze the characteristics of both types of cells. Here is a step-by-step solution to the question:

### Step-by-Step Solution:

1. **Understanding Prokaryotes and Eukaryotes**:
- Prokaryotes are organisms whose cells lack a true nucleus and membrane-bound organelles. They are generally unicellular.
- Eukaryotes, on the other hand, have cells that contain a true nucleus enclosed by a nuclear membrane and have various membrane-bound organelles. They can be unicellular or multicellular.

2. **Identifying Key Features**:
- Prokaryotic cells have a nucleoid region where the genetic material is located, which is not surrounded by a membrane.
- Eukaryotic cells have a defined nucleus that is surrounded by a nuclear membrane.
- Prokaryotes lack membrane-bound organelles (like mitochondria, endoplasmic reticulum, etc.), whereas eukaryotes have these organelles.

3. **Evaluating the Options**:
- **Option 1**: Prokaryotes are unicellular while eukaryotes are multicellular. (Incorrect, as some eukaryotes are unicellular.)
- **Option 2**: Prokaryotes are aquatic while eukaryotes are terrestrial. (Incorrect, as both can be found in aquatic and terrestrial environments.)
- **Option 3**: Prokaryotes are structurally less complex than eukaryotes. (Correct, as prokaryotes lack membrane-bound organelles and have a simpler structure.)
- **Option 4**: Prokaryotes lack a cell membrane while eukaryotes do not. (Incorrect, as prokaryotes do have a cell membrane.)

4. **Conclusion**:
- The distinguishing feature that sets prokaryotic organisms apart from eukaryotic organisms is that prokaryotes are structurally less complex than eukaryotes due to the absence of membrane-bound organelles.

### Final Answer:
The correct distinguishing feature is: **Prokaryotes are structurally less complex than eukaryotes.**

---