The factors that determines the rate of diffusion in the biological system include: temperature, size of the particles, diffusion distance and concentration gradients. Of all these factors, the most important one is the TEMPERATURE.
The relationship between temperature and the rate of diffusion is a direct one, that is, the higher the temperature the higher the rate of diffusion and vice versa. At high temperature the molecules in the particles move faster because they have higher amount of energy.
12. Cells
13. Tissue
14. Motor Neurons
15. Energy
16. Water
17. Microscope
It's A and D. Those are the only two that make since and those are the only right ones. The other ones don't even exist...