A heavy border with a small box in the bottom right corner, known as the Fill Handle.
the active cell
The cell membrane is the thing that surrounds the cell. The cell membrane contains proteins that allow active transport of molecules in and out of the cell.
Yes you can.
Yes, the active cell is outline in black.
active cell
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.
At any one time you can only be working on one cell in Excel, like when you are typing data. Even if you have many cells selected, only one can actually be used. That cell is the active cell. All other cells are inactive. So an inactive cell is any cell that is not the active cell.
cell contents
If you select one cell, it will be active. However, if you select multiple cells at once, only one can be the active cell. That is usually the cell you select first.
It could be called the current cell.
yes
To format a cell in excel right click on it, then on the thing that pops up click on format cell