-Dr. Walter Snelling discovered in 1911 -it is a gas becomes a liquid under moderate pressure or when cold
-it is a portable energy source used in Barbecue grills in hot air balloons

what is it?

He discovered Propane gas

b

is correct hope this   also i learnd this in middle school

metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). the change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. i hoped i !