Bilaterally symmetrical animals have a . A) nerve net. B) centralized nervous system. C) diffuse nervous system. D) a nervous system with ten brains. E) nervous system that senses chemicals only. g

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

d. planting trees

the trees take in carbon to make oxygen.