Final answer:
Capsules do not absorb basic stains and are repelled by acidic stains due to their nonionic and negatively charged properties, respectively.
Step-by-step explanation:
Capsule staining is a laboratory technique used to visualize bacterial capsules, which are protective structures surrounding certain bacterial cells. The capsule is composed of complex polysaccharides and glycoproteins and is not easily visible under a standard microscope. Capsules are important virulence factors for some pathogenic bacteria, as they can help the bacteria evade the host's immune system.
Because capsules have a nonionic nature, they do not absorb most basic stains and therefore, basic stains will not adhere to them. On the other hand, acidic stains are repelled by the negatively charged cell walls of the capsules, making them a negative stain for capsules.