Table of contents

1. Introduction to Biology2h 40m
2. Chemistry3h 40m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 20m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 52m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport2m
- Water Potential
  2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System10m
- Digestion
  3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 57m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System4m
- Endocrine System
  4m
44. Animal Reproduction2m
- Animal Reproduction
  2m
45. Nervous System55m
- Neurons and Action Potentials
  8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

1. Introduction to Biology

Experimental Design

General Biology

1. Introduction to Biology

Experimental Design

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Multiple Choice

Should an experiment test only one variable at a time? Why or why not?

Yes, an experiment should test only one variable at a time. That way, the experiment will have to be performed only once.

No, it is not necessary to test only one variable per experiment, especially when time is of the essence.

As long as the experiment is repeated a sufficient number of times, it does not matter how many variables are used.

Yes, an experiment should test only one variable at a time. This ensures that the experimental outcome is clearly due to one identifiable factor.

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Verified step by step guidance

Understand the concept of a controlled experiment: A controlled experiment is designed to test the effect of a single variable while keeping all other variables constant.

Identify the independent and dependent variables: The independent variable is the one that is changed or controlled in a scientific experiment to test its effects on the dependent variable.

Recognize the importance of isolating variables: By testing only one variable at a time, researchers can determine the specific impact of that variable on the outcome, ensuring that the results are due to the variable being tested and not other factors.

Consider the role of control groups: A control group is used as a baseline to compare the results of the experimental group, which helps in understanding the effect of the independent variable.

Acknowledge the importance of repeatability: Repeating the experiment with the same conditions ensures that the results are consistent and reliable, further validating the effect of the single variable being tested.