Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. 15. Almost half of turtles and tortoises are known to be threatened with A. extinct B. extinction C. extinctive D. extinctly is the natural environment in which a plant or animal 16. lives. A. Habitat Breeding B. Reserve C. D. research 17. Panda is one of the species which are currently of extinction danger A. on B. in C of D. with is the existence of a wide variety of plant and animal 18. species living in their natural environment. A. Biodiversity B. Conservation C. Urbanization D. Destruction It isn't 19. “Do you have to buy this hat" --“ No, I necessary." A. mustn't B. don't need C. needn't D. won't 20. You A. need _keep it secret or they’ll kill you. C. may B. can D. must