What issue does the author highlight in relation to students relying on the free Web for research?

The author emphasizes that when students rely on the free Web for their research, they often encounter significant gaps in information, referred to as "research holes." This issue arises because not all information available online is credible or comprehensive. Students may overlook essential resources, rely on superficial content, or struggle to differentiate between high-quality and low-quality information. These research holes can lead to incomplete understandings of their topics, thereby hindering their learning process.

In contrast, the other options do not accurately capture the essence of the issue described. For instance, the notion that students have too many sources from the Web suggests an abundance of information, which might imply a positive situation rather than addressing the challenge of navigating that information effectively. The idea that students enhance their learning faster overlooks the quality and depth of understanding that often require reliable and thorough research materials. Lastly, the statement about students being indifferent towards physical libraries does not directly relate to the challenges posed by using the Web as their primary research tool, and it fails to capture the potential deficiencies that come with exclusively utilizing online resources.