Which of the following elements is a metal?
a. boron
c. magnesium
b. nitrogen
d. carbon select the best answer from the choices provided a b c d?

How have the greenhouse gasses increased from the year 2000 to 2018

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this

How does concentration affect reaction rate