Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
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 6m
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

35. Soil

Soil and Nutrients

General Biology

35. Soil

Soil and Nutrients

Previous problemNext problem

Struggling with General Biology?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Which soil horizon is typically richest in organic material and is most affected by climate variations?

R horizon

B horizon

O horizon

C horizon

Previous problemNext problem

Verified step by step guidance

Understand the concept of soil horizons: Soil horizons are layers of soil that differ in composition, texture, and color. They are labeled as O, A, B, C, and R horizons, each with distinct characteristics.

Learn about the O horizon: The O horizon is the topmost layer of soil, primarily composed of organic material such as decomposed leaves, plants, and microorganisms. It is rich in nutrients and plays a vital role in supporting plant growth.

Recognize the role of climate: Climate variations, such as temperature and precipitation, significantly affect the O horizon. For example, warmer and wetter climates promote faster decomposition of organic matter, while colder or drier climates slow down this process.

Compare the O horizon to other horizons: The R horizon is bedrock, the C horizon consists of weathered parent material, the B horizon accumulates minerals like clay, and the A horizon is a mix of organic material and minerals. None of these are as rich in organic material as the O horizon.

Conclude that the O horizon is the correct answer: Based on its composition and sensitivity to climate variations, the O horizon is the soil layer richest in organic material and most affected by environmental factors.