3. The panda's ______ habitat is the bamboo forest. a. nature b. natural c. naturalized d. naturally 4. Learners can feel very ______ if an exercise is too difficult. a. courageous b. encouraging c. discouraged d. discouragingly 5. The ______ friendly products are designed not to harm the natural environment. a. environment b. environmental c. environmentally d. environmentalism 6. The waste from the chemical factory is extremely ______. a. harm b. harmful c. unharmed d. harmless 7. People are destroying the air by adding ______ to it. a. pollutants b. polluters c. pollution d. polluted 8. .________ finds the treasure is entitled to twenty percent of it. a. Who b. The people who c. Whoever d. Man who 9. The instrument panel of a light airplane has at least a dozen instruments ___________. a. the pilot must watch b. what the pilot must watch c. which the pilot must watch them d. such that the pilot must watch 10. Dr Seuss, _____ was Theodor Seuss Geisel, wrote and illustrated delightfully humorous books for children. a. his real name b. who had as his real name c. with his real name d. whose real name 11. Diamonds are often found in rock formations called pipes, _____ the throats of extinct volcanoes. a. in which they resemble b. which resemble c. there is a resemblance to d. they resemble 12. If we had known your new address, we _____ to see you. a. came b. will come c. would come d would have come