The answer is diffusion.
Facilitated diffusion is a process by which molecules are transported across the plasma membrane with the help of membrane proteins.
Unicellular organisms excrete waste by a contractile vacuole. A vacuole is membrane-enveloped organelle in a cell that is found in lots of microorganism. It expands, filling with water then contracts, removing all of its contents to the exterior of the cell.
The correct answer is option glucose.
The glucose can be used as the immediate source of the energy. The cells can utilize the glucose to form the ATP molecules, which can be used as a source of energy by the body of the organism. The cellulose, chitin, and the glycogen are the polymers, they can only be utilized, once they are broken down into simpler forms.
Either C or D. I think C, but I'm not too sure...