Which number should be placed before f2 on the reactants side equation to make equation balanced? xe + > xef4

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

When the speed of the bottle is 2 m/s, the average maximum height of the beanbag is m.