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 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 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 57m
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

31. Invertebrates

Lophotrochozoans

General Biology

31. Invertebrates

Lophotrochozoans

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0:54 minutes

Problem 1`

Textbook Question

A land snail, a clam, and an octopus all share
a. A mantle
b. A radula
c. Gills
d. Distinct cephalization

Verified step by step guidance

Begin by identifying the common phylum to which a land snail, a clam, and an octopus belong. All three are part of the phylum Mollusca.

Understand the characteristics of the phylum Mollusca. Members of this phylum typically have a mantle, which is a significant part of their anatomy.

Consider the function of the mantle in mollusks. The mantle is a layer of tissue that covers the body and is responsible for secreting the shell in many mollusks.

Evaluate the other options provided: a radula is a specialized feeding organ found in some mollusks, but not all (e.g., clams do not have a radula). Gills are present in aquatic mollusks, but not in land snails. Distinct cephalization refers to the development of a head region, which is more pronounced in octopuses than in snails or clams.

Conclude that the shared feature among a land snail, a clam, and an octopus is the mantle, as it is a defining characteristic of the phylum Mollusca.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mantle

The mantle is a significant part of mollusks, including snails, clams, and octopuses. It is a layer of tissue that covers the visceral mass and is responsible for secreting the shell in those mollusks that have one. The mantle also plays a role in respiration and excretion, making it a crucial anatomical feature across different mollusk species.

Radula

A radula is a specialized feeding organ found in most mollusks, except bivalves like clams. It is a ribbon-like structure covered with tiny teeth used to scrape or cut food before ingestion. The presence or absence of a radula is a key distinguishing feature among mollusk classes, highlighting differences in feeding strategies.

Cephalization

Cephalization refers to the concentration of sensory organs and nerve cells at the anterior end of an organism, forming a head region. This feature is prominent in octopuses, which have a well-developed head and brain, but is less distinct in snails and clams. Cephalization is associated with increased complexity and specialization in the nervous system, enhancing an organism's ability to interact with its environment.