A bookmark is a saved link to a web page that allows you to quickly and easily access it later without needing to remember the URL. Bookmarks are a common feature in web browsers and are used to keep track of favorite or important websites.

In MS Word, pressing Shift + F3 changes the case of the selected text. It cycles through three options:

1. Lowercase (e.g., "text")
2. Uppercase (e.g., "TEXT")
3. Title Case (e.g., "Text")

In MS Excel, the dollar sign ($) is used to convert a relative address to an absolute address. By placing the $ before the column letter, row number, or both, you lock that part of the reference, so it does not change when copying the formula to another cell.

For example:

• $A$1: Absolute reference to both column A and row 1.
• A$1: Absolute reference to row 1, but relative reference to column A.
• $A1: Absolute reference to column A, but relative reference to row 1.

In Microsoft Word, pressing F7 is the shortcut key used to open the Spelling and Grammar check. This allows you to quickly review and correct spelling and grammar errors within your document.

The first generation of computers (1940-1956) used vacuum tubes for circuitry and magnetic drums for memory. Vacuum tubes were large, generated a lot of heat, and were inefficient by today's standards, but they were the primary technology for computers at that time.