Me : )) 15 points (chemistry)
define substance and give two examples of things that are substances

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 number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.