the camera
The instrument that was necessary for Cell Theory to be developed is the microscope.
Microscope
Microscopes.
light microscope
what instrument was necessary for the development of the cell theory? you would need cells. you can't have the organism without cells. you can't have a school without people. so the answer is cells.
newtons law of motion states blah blah blah
The flash light and the ruler and goggles
The name of the theory that Schleiden and Schwann developed is the cell theory.
Microscope
the cell thery
it is essential for everything
All the cell organelles present in the cell are essential as each one of them have their specific function.