1. The horizontal lines displayed in the plot area of a chart in MS Excel 2010 are called gridlines.

2. Types of Grid Lines in MS Excel 2010 –

- Main grid lines: These show the key values of the data ranges. They have usually displayed every 5 or 10 values.

Secondary grid lines: These show the intervals between data ranges. They usually appear after every 1 or 2 values.

Actually, in MS PowerPoint (and most other word processing applications), the key combination to move down one paragraph is "Enter". Pressing the "Enter" key moves the cursor to the next paragraph. If you want to move the cursor down one line within the same paragraph, you can use the "Down Arrow" key. There isn't a specific default key combination to move down one paragraph in PowerPoint; it's more about using the "Enter" key to start a new paragraph.

In Microsoft Word 2019, you can add page numbers to your document by using the "Insert" tab. The "Insert" tab contains various options, including the "Page Number" option, which allows you to insert page numbers at different locations in your document.

In MS PowerPoint, the key combination to open the 'Save As' dialog box is F12. Pressing F12 opens the 'Save As' dialog box directly, allowing you to save the current presentation with a new name or in a different location.

In Excel 2003, the number of rows is 65,536. Each worksheet in Excel 2003 consists of 65,536 rows and 256 columns.