Table of contents

1. Introduction to Biology2h 42m
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 12m
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 53m
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 Transport1h 2m
- Water Potential
  1h 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 System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 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

Introduction to Taxonomy

General Biology

1. Introduction to Biology

Introduction to Taxonomy

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Multiple Choice

Which statement best contrasts roundworms and tapeworms?

Tapeworms have a segmented body with a true coelom, while roundworms are unsegmented and acoelomate.

Tapeworms possess a body cavity, whereas roundworms do not.

Roundworms are exclusively parasitic, while tapeworms are always free-living.

Roundworms have a complete digestive tract, while tapeworms absorb nutrients directly through their body surface.

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Verified step by step guidance

Step 1: Begin by understanding the key biological characteristics of roundworms and tapeworms. Roundworms (phylum Nematoda) are unsegmented worms with a complete digestive tract, meaning they have both a mouth and an anus for food processing. Tapeworms (phylum Platyhelminthes, class Cestoda), on the other hand, lack a digestive system entirely and absorb nutrients directly through their body surface.

Step 2: Analyze the structural differences between the two organisms. Roundworms are cylindrical and possess a pseudocoelom, which is a fluid-filled body cavity that is not completely lined by mesoderm. Tapeworms are flat, segmented, and lack a true body cavity (acoelomate).

Step 3: Consider the mode of nutrient acquisition. Roundworms ingest food through their mouth, process it in their digestive tract, and expel waste through the anus. Tapeworms, being parasitic, attach to the host's intestinal lining using specialized structures like hooks and suckers, absorbing pre-digested nutrients directly through their tegument (body surface).

Step 4: Evaluate the ecological roles and lifestyles. Roundworms can be free-living or parasitic, depending on the species. Tapeworms are exclusively parasitic and rely on a host for survival, often causing harm to the host organism.

Step 5: Based on the above analysis, identify the correct statement that contrasts roundworms and tapeworms. The correct answer is: 'Roundworms have a complete digestive tract, while tapeworms absorb nutrients directly through their body surface.' This highlights the fundamental difference in their digestive systems and nutrient acquisition methods.