Final answer:
Skimming is best used for previewing a chapter in a content-area textbook as it provides an initial understanding of the main ideas and structure without detailed analysis.
Step-by-step explanation:
Skimming is likely to be the most effective strategy for accomplishing the task of previewing a chapter in a content-area textbook. This reading method involves quickly going over the text to grasp the main ideas and general overview. It is particularly useful for getting an initial sense of the material's structure, identifying chapter headings, key facts, and important concepts without delving into the finer details of the content.
When it comes to more in-depth tasks such as evaluating the validity of information, synthesizing information for a research report, or studying for specific facts in an exam, skimming might not suffice. These tasks require a more thorough reading and analysis of the material, which could include critically evaluating sources using the SIFT method and engaging with the text to understand complex arguments and evidence.