This statement is a simplified version of the Cell Theory, which is a fundamental principle in biology. Here's a breakdown:

The Cell Theory states:

1. All living organisms are composed of one or more cells. This means that everything from bacteria to humans is made up of cells.

2. The cell is the basic unit of life. Cells are the smallest functional units that can carry out all the processes necessary for life.

3. All cells arise from pre-existing cells. This is the key point – new cells are not created from non-living matter, they are always formed by the division of existing cells.

So, to answer your question directly:

Yes, all cells that exist today came from pre-existing cells. This is a fundamental principle of life and has been supported by a vast amount of scientific evidence.