-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?

What's wrong with this ecological pyramid? (multiple choice)1. secondary consumers should be at the bottom of the pyramid2. the sun has an arrow leading to decomposers 3. primary consumers should come after the sun4. energy retained should increase from the bottom to the top5. the sun should be at the bottom of the pyramid