Identify one way Ultra Violet Rays can be harmful to humans? Thank you so much!

The element that has the greatest electronegativity is

Precision can be defined as the o exact center of a data set. o reproducibility of a measured value. o correlation between two variables that are measured in a data set agreement between a measured value and an accepted value.

The valence of aluminum is +3, and the valence of the chlorine is -1. the formula fir the aluminum chloride is correctly written as