Assuming, that the buffer refers to phosphate buffered saline, the advantages are that the pH is stable and that the solution is isotonic to the cells. The cells, therefore, do not change shape. The solution is used to make dilutions of the cells and to separate the cells from each other. The buffer contains sodium chloride, sodium phosphate. Other recipes also contain potassium chloride and potassium phosphate.
How should you remove extra water from a wet mount slide? Remove excess water with a piece of filter paper or tissue paper. Have a look at the following video for an explanation on how to make a wet-mount slide: Making a wet mount microscope slide
How can I make a sample stick to a microscope slide? This depends on the sample. Bacterial suspensions should be first dried on the slide and then heat-fixed. The slide should be briefly heated over a Bunsen burner. This will immobilize the cells.
How to permanent mount algae? They are frequently mounted in a water-based mounting medium, such as glycerin gelatin.
Is Spirogyra microscopic? The individual cells can only be seen with the microscope, the whole algae can naturally be seen with the unaided eye as thin cotton-like filaments.
If you observed the same organism on a prepared slide and a wet mount how would the images compare? This depends on the refractive index of mounting medium. Wet mounted specimens can move. Because they were generally not fixed in alcohol, they also do not show artifacts and (possible) shrinkage.