Karen is studying an area that has many trees and goes through all four seasons. The trees lose their leaves as the seasons progress. Which biome is she studying?

deciduous forest
grassland
desert
topical rain forest

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds