Read the passage about riparian vegetation, winter cover, and the importance of trees and shrubs along streams. Then answer the question. What topic is mainly discussed in the second paragraph of this passage?

Introduction / Context:
The passage about riparian vegetation contains several paragraphs that each highlight a different aspect of streamside ecology. The second paragraph in particular discusses trees, shrubs, and woody plants in riparian zones. The question asks what is discussed in that specific paragraph, so we must distinguish its focus from the topics of the other parts of the passage, such as winter cover for birds, insects, dead trees, and disease organisms.

Given Data / Assumptions:

• The second paragraph explains that in many parts of the arid West, trees and shrubs are found only in riparian areas.
• It states that woody plants are very important as winter cover for wildlife, including game birds like pheasants and turkeys.
• It mentions that this winter cover can be the main limiting factor for game bird populations.
• It also notes that woody vegetation provides hiding cover and browse for many other birds and mammals.
• Other paragraphs talk about dead trees, insects, diseases, and contacting extension agents if trees begin to die.

Concept / Approach:
To identify the main topic of a paragraph, we look for its central idea rather than isolated details. In the second paragraph, nearly every sentence refers to trees, shrubs, woody plants, and the cover they provide. Game birds and other wildlife are mentioned as users of this cover, which supports the central theme. We should not confuse this with the later discussion of insects in dead trees, or with water quality details that do not appear explicitly in the second paragraph.

Step-by-Step Solution:
Step 1: Recall that the second paragraph begins by noting that in many arid regions trees and shrubs grow only in riparian zones. Step 2: It then describes how woody plants provide winter cover for wildlife, including game birds, and how this cover can limit their populations. Step 3: The paragraph also explains that woody vegetation offers hiding cover and browse for many species of birds and mammals. Step 4: Evaluate option C, which states that the role of trees and shrubs in riparian areas, especially as winter cover, is discussed. This summarises the paragraph accurately. Step 5: Option A mentions types of birds in riparian areas, but the detailed list of bird species appears later when the passage turns to dead trees and insects. Step 6: Option B refers to water purity, which is not the main focus of the second paragraph. Step 7: Option D restricts the discussion to game bird populations, but the paragraph also talks about many other species that use woody vegetation. Step 8: Option E brings in soil chemistry, which is not discussed in this paragraph.

Verification / Alternative check:
One quick verification method is to ask yourself what you would use as a heading for the second paragraph. A suitable heading would be something like Importance of woody vegetation as winter cover in riparian areas. That is very close to option C. None of the other options could serve as accurate headings because they either focus on different parts of the passage or introduce ideas that are not central to that paragraph.

Why Other Options Are Wrong:
Option A is wrong because the main list of bird species is tied to dead trees and insect feeding, not to the general definition of winter cover. Option B is wrong because there is no specific discussion of water purity or chemistry in that paragraph. Option D is wrong because the paragraph mentions many kinds of wildlife, not only game birds, so its scope is wider. Option E is wrong because the paragraph does not focus on soil chemistry at all.

Common Pitfalls:
Students sometimes latch onto one or two words, such as game birds, and assume that is the entire subject of a paragraph. It is important to read all the sentences and see what unites them. In this case, trees, shrubs, and woody vegetation appear again and again, showing that the paragraph is really about the role of these plants in riparian areas, especially in relation to winter cover and wildlife habitat.

Final Answer:
The second paragraph mainly discusses the role that trees and shrubs play in riparian areas, especially as winter cover for wildlife.