Question

1. why is mercury no longer used in many devices?

Explanation:

Mercury is a toxic heavy metal. When devices containing mercury break or are disposed of improperly, mercury can be released into the environment (air, water, soil). It bioaccumulates in ecosystems, harming wildlife and humans (e.g., affecting nervous systems). Regulatory efforts and the development of safer alternatives (like digital thermometers instead of mercury thermometers) have led to its phase - out from many devices to reduce environmental and health risks.

Answer:

Mercury is toxic; improper disposal/release harms the environment (bioaccumulation, ecosystem damage) and human health (nervous system effects). Safer alternatives and regulations also drive its phase - out from many devices.