nicotine
abstract
alternative
biological
bough
branches
breath
breathe
bronchiole
cancer
care
cigarette
clean
concept
death
dirty
eco
ecology
foliage
green
growth
healthy
human
idea
internal
isolated
leaf
life
lungs
medical
medicine
nature
organ
plant
revival
save
side
skeleton
smoker
symbol
tobacco
trachea
tree
two
vital