Find the Incorrect statements
a. In hemodialysis, the dialysing unit contains a coiled cellophane tube surrounded by dialysing fluid, have the same composition as that of plasma except nitrogenous waste.
b. The production of uric acid is enhanced by excessive metabolism of nucleic acids.
c. Ionocytes in the gill membrane of fresh water fish can passively import `Na^(+) and Cl^(-)` from surrounding water.
d. Marine teleosts remove nitrogenous waste in the form of urea.

Options

A. a & b only
B. c & d only
C. b & c only
D. a & d only

Answer

To find the incorrect statements among the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A**: "In hemodialysis, the dialyzing unit contains a coiled cellophane tube surrounded by dialysing fluid, have the same composition as that of plasma except nitrogenous waste."
- **Analysis**: This statement is generally correct. In hemodialysis, the dialysate (dialyzing fluid) is designed to have a composition similar to plasma but without the nitrogenous waste products, allowing for their removal from the blood through the cellophane membrane.

2. **Statement B**: "The production of uric acid is enhanced by excessive metabolism of nucleic acids."
- **Analysis**: This statement is also correct. Uric acid is a product of purine metabolism, and excessive breakdown of nucleic acids (which contain purines) can lead to increased production of uric acid.

3. **Statement C**: "Ionocytes in the gill membrane of fresh water fish can passively import Na^(+) and Cl^(-) from surrounding water."
- **Analysis**: This statement is incorrect. Freshwater fish actively transport Na^+ and Cl^- ions into their bodies because the concentration of these ions is lower in freshwater compared to their body fluids. Thus, they cannot passively import these ions.

4. **Statement D**: "Marine teleosts remove nitrogenous waste in the form of urea."
- **Analysis**: This statement is incorrect. Marine teleosts (bony fish) primarily excrete nitrogenous waste in the form of ammonia due to the high solubility of ammonia in water. Some marine organisms do excrete urea, but it is not the primary method for marine teleosts.

### Conclusion:
The incorrect statements are **C** and **D**.