Final answer:
Chlorhexidine does not damage Alison's tissue because it selectively targets and kills bacteria without harming human tissue.
Step-by-step explanation:
Chlorhexidine does not damage Allison's tissue because it has a selective mode of action against bacteria. Chlorhexidine is a bisbiguanide compound and is commonly used as an antiseptic and disinfectant.
It disrupts the bacterial cell membrane, causing cell contents to gel and leading to cell death. However, it does not have the same effect on human tissue because human cells do not have the same type of membrane targeted by chlorhexidine. Therefore, it selectively targets and kills bacteria without causing harm to human tissue.