A __________ can be used to search the web for information specified by the user.

A search engine is specifically designed to search the web for information based on user queries. It indexes vast amounts of data from websites and allows users to enter keywords or phrases to retrieve relevant results. Popular examples include Google, Bing, and Yahoo.

This functionality is what distinguishes a search engine from other options provided. A browser, while integral to accessing the internet, serves as the software interface through which users view websites, not something that autonomously conducts searches based on user-inputted terms. A modem facilitates internet connectivity, translating data between a computer and the internet, thus is not directly related to searching for information. Lastly, a URL (Uniform Resource Locator) is the specific address used to access a website or resource on the web, making it a tool for navigation rather than a means to conduct searches.