Question

The cell theory was given by
A. Schlieden and Schwann
B. Albrecht von Roelliker
C. Hooke
D. Haeckel

Answer 1

Hint: Robert Hooke explained the smallest living structure in the body. Scientists named Matthias Schleiden and Theodor Schwann and also Rudolf Virchow contribute to the concept of cell theories. Cell theory postulated mainly three concepts about organization of cells.

Complete answer:
The basic functional and structural unit of life is called a cell. Cell was discovered by Robert Hooke in 1665, after the invention of the microscope. The historic scientific theory also called cell theory tells that living organisms are made of cells, that they are the basic structural/organizational unit of all organisms. The chemical composition of all the cells is the same. Study of cells is called cell biology. Scientists named Matthias Schleiden and Theodar Schwann gave cell theory in 1839.

The modern cell theory postulated that:
-Every living organism is composed of one or more cells.
-The most basic unit of life is known as a cell.
-All the cells arise only from pre-existing cells.

In 1855, Rudolf Virchow gave the above mentioned third point.
From the above information we have found that cell theory was given by Schleiden and Schwann.

Hence, the correct answer is option (A).

Note: The modern version of cell theory includes new facts about cells that are: flow of energy occurs within the cells, hereditary information (DNA) transfers from cell to cell and generation to generation. It also explained that the basic chemical composition of the cells is the same in all the cells. The internal contents of the cells were called protoplasm and described as jelly-like substances.