I checked out my Excel 2007 software and it looks like the closest answer would be 'unmerging' the cell. Here is direct text for their help website though:
You can't split an individual cell, but you can make it appear as if a cell has been split by merging the cells above it. For example, you want to split cell A2 into three cells that will appear, side-by-side, under cell A1 (you want to utilize cell A1 as a heading). It is not possible to split cell A2, but you can achieve a similar effect by merging cells A1, B1, and C1 into one, single cell. You then enter your data in cells A2, B2, and C2. These three cells appear as if they are split under one larger cell (A1) that acts as a heading.
splitting
In Excel 2003, it was called splitting. To bring them back together it is called merging.
If you make two or more cells into one cell, that is called merging the cells.
The chromosomes
It is called Merging in Microsoft Excel. There is one issue though, you gotta be careful when merging as either of the cell value could get deleted.
spindle fibers
font size
Clicking a cell will select it. You can select more by dragging out over them.
Depending on what you mean, it could be a range, which is a group of cells in Excel, that can be referenced in a formula as a block, but they are not a single cell then. You could be referring to cells that have been merged, in which case Excel treats them as a single cell.
Morpholinos: more predictable, more specific and more stable than siRNA
What you initially see dividing one cell from another are the gridlines. Borders allow you to put more solid boxes or other styles of boxes around the cells. They are known as Borders.
A saved workbook in excel is called a spreadsheet. It contains one or more worksheets, which is an arrangement of columns and rows.
At any moment in time, at least one cell has to be selected in Excel. It is known as the active cell. There has to be a focal point so that data or formulas can be typed in. Even when more than one cell is selected, there is only one active cell. Which cell is the active cell can be changed at any time, but there always has to be an active cell. If there isn't then, before you do anything, you would have to make a cell active. Cells are fundamental to Excel so there has to be an active cell at all times.