Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

Cell theory asserts the cell is
constituent unit of beings.

Before the of the cell, was
not recognized living beings were
of building blocks cells.

The cell is one of basic
theories of .