How many statements about diffusion is /are false ?
(i) The diffusion rate depends on the size of the substrate.
(ii) Diffusion across the membrane depends upon its solubility in lipids.
(iii) Membrane protein provides sites for a hydrophilic substance to cross the membrane.
(iv) Facilitated diffusion is carried out by Proteins .

Options

A. 0
B. 1
C. 2
D. 3

Answer

To determine how many statements about diffusion are false, let's analyze each statement one by one:

1. **Statement (i): The diffusion rate depends on the size of the substrate.**
- This statement is **true**. The rate of diffusion is influenced by the size of the molecules; smaller molecules generally diffuse faster than larger ones.

2. **Statement (ii): Diffusion across the membrane depends upon its solubility in lipids.**
- This statement is **true**. The ability of a substance to diffuse across a membrane is largely determined by its lipid solubility. Lipid-soluble substances can pass through the lipid bilayer more easily than those that are not.

3. **Statement (iii): Membrane proteins provide sites for a hydrophilic substance to cross the membrane.**
- This statement is **true**. Membrane proteins, especially channel and carrier proteins, facilitate the transport of hydrophilic substances across the hydrophobic lipid bilayer of the membrane.

4. **Statement (iv): Facilitated diffusion is carried out by proteins.**
- This statement is **true**. Facilitated diffusion specifically involves the use of membrane proteins to help transport substances across the membrane without the expenditure of energy.

Now, let's summarize the findings:
- All four statements (i, ii, iii, and iv) are true.

Therefore, the answer to the question "How many statements about diffusion is/are false?" is **0**.

### Final Answer:
**0 statements are false.**