Directions. Choose the letter of the correct answer. Write your answer in the answer sheet provided. 1. How many percent of nitrogen is present in the atmosphere? A. 48 % B. 58 % C. 68 % D. 78 % 2. Which of the following are examples of bacteria responsible for the conversion of atmospheric nitrogen into ammonia? A. Azotobacter C. Nostoc B. Clostridium & Rhizobium D. All of the above 3. Which part of the roots of leguminous plant the nitrogen fixing bacteria are found? A. Node B. Internode C. Nodules D. Main root 4. Which of the following is/are example of leguminous plant? A. Mango B. Zinger C. Mongo D. Squash 5. What group of organism(s) is/are responsible for the process of ammonification? A. Protists B. Fungi & Bacteria C. Plantae D. All of the above 6. What group of bacteria that convert nitrogen from air into nitrates? A. nitrogen-fixing bacteria C. decomposing bacteria B. denitrifying bacteria D. streptococcus bacteria 7. Which of the following elements comprises the largest portion of the earth atmosphere? A. oxygen B. carbon C. nitrogen D. sulfur 8. Which of the following processes converts ammonia to nitrites then into nitrates? A. ammonification B. nitrification C. denitrification D. nitrogen fixation 9. Which of the following processes by which nitrogen is returned back into the atmosphere? A. ammonification B. nitrification C. denitrification D. nitrogen fixation 10. Which of the following processes that breaks down dead organic matter and waste to produce ammonia? A. ammonification B. nitrification C. denitrification D. nitrogen fixation 11. What do you call to a process by which nitrogen gas is converted into nitrates which involves making of fertilizers by human? A. industrialization C. industrial action B. industrial fixation D. industrial fertilization 12. Which of the following can convert nitrogen gas into nitrates in the atmosphere? A. rain B. wind C. clouds D. lightning​