Which of the following can be used to gather numeric data on student views?

Google+ Polls is the correct choice for gathering numeric data on student views. Polls are specifically designed to collect responses from participants in a straightforward manner. When you create a poll on Google+, you can ask a question and provide various options for respondents to choose from, allowing you to quantify their opinions or preferences directly. The responses can be easily analyzed to obtain concise, numeric data reflecting students' views.

While the other options have their unique functionalities, they are not primarily designed for the purpose of collecting this type of feedback. YouTube is focused on video sharing, and while you can engage with viewers through comments or video polls, it does not provide a structured format specifically for gathering and quantifying responses. Google Sheets is great for organizing and analyzing data, but it doesn't inherently gather data on its own; it serves as a tool for data management. Google Sites allows for the creation of websites but also does not have a built-in mechanism for poll-like data collection.

In summary, Google+ Polls stands out as the most suitable tool for gathering numeric data on student views because of its clear, targeted approach to polling, which directly facilitates the collection of measurable responses.