Is the awnser a b c or d ?

It would be: C

Explanation:

"The elements [on the periodic table] in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons. They are the electrons involved in chemical bonds with other elements. Every element in the first column (group one) has one electron in its outer shell."

I hope this helps! Have a nice night! :D

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.