Analisis

TEACHER RESOURCES

Answer Key
Directed Reading A
SECTION: ASKING ABOUT LIFE
1. life science 2. diversity 3. Answers may vary. Sample answer: Where does it live? 4. anyone 5. anywhere—in a laboratory, on farms, in forests, on the ocean floor, in space, for business, hospitals, government agencies, universities, as teachers 6. his or her curiosity 7. AIDS 8. inherited 9. Many environmentalproblems are caused by people’s misuse of natural resources. 10. By learning about the needs of Siberian tigers, scientists hope to develop a plan that will help them survive. 14. Answers may vary. Sample answer: so other scientists may repeat the experiments to see if they get the same results; so scientists with similar interests can compare hypotheses and form consistent explanations

SECTION:SCIENTIFIC MODELS
C C B A D theory law Scientific theories are used to explain observations and to predict what might happen. A scientific law is a summary of observations and tells us what will happen. 9. theories, facts, laws 1. 2. 3. 4. 5. 6. 7. 8.

SECTION: SCIENTIFIC METHODS
1. making observations; forming a hypothesis 2. The order depends on what works best to answer their questions. 3. B4. hypothesis 5. testable 6. prediction 7. an experiment that tests only one factor at a time by using a comparison of a control group with one or more experimental groups 8. a factor that differs between the control group and experimental groups 9. planning 10. The more organisms tested, the more certain scientists can be of the data they collect in an experiment. 11. Answers may vary. Sampleanswer: in a graph or a data table 12. Both are helpful. Either way, the scientist has learned something, which is the purpose of using scientific methods. 13. another investigation

SECTION: TOOLS, MEASUREMENT, AND SAFETY
1. Life scientists use tools to make observations and to gather, store, and analyze information. 2. the application of science for practical purposes 3. 1946 4. to creategraphs, solve complex equations, analyze data, share data and ideas, and publish reports 5. B 6. D 7. C 8. A 9. C 10. It helps scientists share and compare observations and results. Almost all units are based on the number 10, which makes conversions easy. 11. millimeter 12. area 13. square 14. volume 15. liters, milliliters, cubic meters, cubic centimeters, and cubic millimeters 16. mass

Originalcontent Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.

Holt Science and Technology

95

The World of Life Science

TEACHER RESOURCES
17. kilograms, metric tons, and grams 18. temperature 19. degrees Celsius, degrees Fahrenheit, and kelvins 20. Answers may vary. Sample answer: Ask teacher for permissionand read the lab procedure carefully. 21. B 22. D 23. C 24. G 25. F 26. I 27. E 28. A 29. H

SECTION: TOOLS, MEASUREMENT, AND SAFETY
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. tools technology computer analyze data B D C A B C A A C D A B D B C A

Directed Reading B
SECTION: ASKING ABOUT LIFE
1. 2. 3. 4. 5. B A D D C 6. 7. 8. 9. B diseases inherited tigersSECTION: SCIENTIFIC METHODS
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. scientific methods asking questions counting accurate hypothesis if-then factor controlled experiment variable A A A C A B

Vocabulary and Section Summary
SECTION: ASKING ABOUT LIFE
1. life science: the study of living things

SECTION: SCIENTIFIC METHODS
1. scientific methods: a series of steps followed to solveproblems 2. hypothesis: an explanation that is based on prior scientific research or observations and that can be tested 3. controlled experiment: an experiment that tests only one factor at a time by using a comparison of a control group with an experimental group 4. variable: a factor that changes in an experiment in order to test a hypothesis

SECTION: SCIENTIFIC MODELS
1. 2. 3. 4. 5. 6. A B A...