Final answer:
Ethidium Bromide is dangerous as it can cause mutations by intercalating with DNA, but it is valuable in molecular biology for its fluorescent properties, which enable visualization of nucleic acids on agarose gels.
Step-by-step explanation:
Ethidium Bromide (EtBr) is considered dangerous because it is an intercalating agent, which means it can slide between DNA bases and potentially cause mutations that can lead to cancer. Despite its risks, EtBr is extremely helpful for molecular biology because it has the ability to bind to DNA and, upon exposure to UV light, fluoresces. \
This property is essential for visualizing nucleic acids on an agarose gel during electrophoresis, a commonly used technique in molecular biology. However, due to its toxicity, care must be taken to avoid exposure, and alternatives like SYBR Green are often used.