Select the incorrect statement.

Options

A. Egg of ostrich is the largest isolated single cell
B. Ribosomes are organelle within the organelle
C. The Shape of the cells may vary with the function they perform
D. Genetic material is present in well defined nucleus in both prokaryotes and eukaryotes

Answer

**Step-by-Step Solution:**

1. **Analyze the Options:**
- We need to evaluate each statement provided in the options to identify which one is incorrect.

2. **Evaluate the First Option:**
- The statement claims that the egg of an ostrich is the largest isolated single cell.
- This is true; the ostrich egg is indeed the largest single cell known, weighing about 1.5 kg.

3. **Evaluate the Second Option:**
- The statement mentions that ribosomes are organelles within organelles.
- This is also correct; ribosomes can be found within other organelles such as the endoplasmic reticulum, mitochondria, and chloroplasts.

4. **Evaluate the Third Option:**
- The statement asserts that the shape of cells may vary with the function they perform.
- This is accurate; different types of cells have distinct shapes that correlate with their specific functions (e.g., nerve cells are long and branched for signal transmission, while muscle cells are spindle-shaped for movement).

5. **Evaluate the Fourth Option:**
- The statement claims that genetic material is present in a well-defined nucleus in both prokaryotes and eukaryotes.
- This is incorrect; eukaryotes have a well-defined nucleus containing their genetic material (DNA), while prokaryotes do not have a true nucleus. Instead, their genetic material is located in a region called the nucleoid, which is not membrane-bound.

6. **Conclusion:**
- After evaluating all the options, the incorrect statement is the fourth one: "Genetic material is present in a well-defined nucleus in both prokaryotes and eukaryotes."

**Final Answer:**
The incorrect statement is: "Genetic material is present in a well-defined nucleus in both prokaryotes and eukaryotes."

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