When scientists set out to test a hypothesis, it is often most practical to try to prove the hypothesis false rather than to prove it is true in all cases. Scientists place great confidence in cell theory, yet it has not been tested in every living thing on the planet. What piece of evidence would cause scientists to decide that cell theory would need to be revised? A. An organism was found with tissues made of something other than cells. B. A cell was found that could continue to divide and reproduce indefinitely. C. An animal cell was found that could harness solar energy as plant cells do. D. Cells were found that used something other than DNA as hereditary material.

The correct answer is:

An organism was found with tissues made of something other than cells. (A)

Explanation:

The postulation of the cell theory is credited to Matthias Schleiden; a German Botanist, Theodor Schwann; a German physician and physiologist, and Rudolf Virchow; a German physician, biologist and anthropologist in 1839.

The Cell Theory has three main aspects which include that;

1. cells are the basic structural and organizational unit of life

2. all living thing are composed of at least one cell

3. all cells in existence, come from pre-existing cells.

Hence, the Cell Theory can be stated as; all living things are made up of cells which are the basic structural and organizational unit of life, and all cells come from pre-existing cells. However, the first statement that 'all living things are made up of cells' is being disputed because viral particles are considered lifeforms, and are not made up of cells

Before the postulation of the Cell Theory in 1839, the belief among scientists was the belief of spontaneous generation, which postulates that living organisms emerged spontaneously from unrelated materials, without necessarily arising from similar organisms.

The success of the Cell Theory can also be owed to the development of the microscope by Robert Hooke, who initiated cell biology.