Each safety sign has components.

Explanation:

A massive asteroid impact would create long-term changes in the atmosphere and climate of the planet. Upon impact, vaporized dirt and rock would fill the atmosphere, blocking sunlight and creating a state of near-permanent darkness and winter-like conditions.

An artesian well is simply a well that doesn't require a pump to bring water to the surface; this occurs when there is enough pressure in the aquifer. The pressure forces the water to the surface without any sort of assistance