A) Nitrogen B) Hydrogen C) Carbon dioxide D) Oxygen
A) Bark B) Fruit C) Roots D) Leaves
A) The clearing of trees in an area. B) The conservation of forests. C) The planting of trees. D) The protection of endangered species.
A) Oxygen B) Carbon monoxide C) Sulfur dioxide D) Nitrogen gas
A) They produce oxygen through photosynthesis. B) They consume carbon dioxide only. C) They grow underwater. D) They absorb heat.
A) About 31% B) About 50% C) About 15% D) About 75%
A) They decrease populations. B) They increase pollution. C) They create deserts. D) They provide shelter and food.
A) Pine B) Maple C) Willow D) Birch |