Final answer:
The key idea in both 'A Legacy of Stone' and 'Trees Rise in the Desert' is the theme of environmental transformation. Evidence supporting this theme would include changes in the landscape or ecosystem. Analysis should integrate specific evidence from the texts and consider competing sources for a comprehensive understanding.
Step-by-step explanation:
The key idea present in both 'A Legacy of Stone' and 'Trees Rise in the Desert' is likely the theme of transformation or restoration of the environment. While specific texts are not provided for direct analysis, this conclusion is supported by the titles and common threads that can be inferred, such as the 'legacy' likely involving some human impact on the environment (stone) and 'trees rising' in a typically barren area (desert), which hints at ecological recovery or change.
The textual evidence to look for would involve descriptions of the environment before and after the transformation, noting any changes in the community, ecosystem, or landscape that are described. One might look for textual evidence that specifically addresses how stone constructions are perhaps being reclaimed by nature or how an area has been revitalized by the planting of trees, significantly altering the desert landscape.
Considering a sentence such as 'Garrison further elaborates on the significance of the textual evidence,' a student would need to identify how Garrison's elaboration connects environmental transformation to the overall thesis. In weighing evidence, especially with regard to themes in literature, it is also crucial to 'consider competing sources about the same topic' to ensure a comprehensive understanding and to 'integrate specific evidence' from both primary and secondary sources to support the main idea.