Question

Schwann and Schleiden were (a) Dutch Biologists
(b) English Biologists
(c) Austrian Biologists
(d) German Biologists

Answer 1

In biology, cell theory is the generally accepted historical scientific theory that living organisms consist of cells, that they are the fundamental structural/organisational unit of all organisms, and that all cells originate from pre-existing cells. This theory was given by Schwann and Schleiden who belonged to a European country whose capital city is Berlin which is the world city of culture, media, politics, etc.

Complete Step by Step Answer:
Schwann and Schleiden were German Biologists. Theodor Schwann was a German doctor and physiologist. The application of cell theory to animals is considered to be his most important contribution to biology. Matthias Jakob Schleiden, along with Theodor Schwann and Rudolf Virchow, was a German botanist and a co-founder of cell theory.

Schleiden proposed in 1839 that any structural component of a plant consisted of cells or the product of cells. He also indicated that cells were formed either inside other cells or from the outside through a crystallization process. Theodor Schwann claimed in 1839 that animals are composed of cells or the result of cells in their structures together with plants. This was a significant development in the field of biology as up to this point nothing was understood about animal structure relative to plants.
Two of the three cell theory tenets were postulated: - One or more cells make up a living organism. - The most fundamental unit of life is the cell. Later, the third tenet was added as Omnis cellula e cellula. This tenet notes Omnis cellula e cellula is in Latin. This has been translated into: - All cells only derive from pre-existing cells which form the third postulate.
In modern cell theory, the widely accepted sections include: - All known living things are formed from at least one or more cells. - From pre-existing cells by division, all living cells arise. - In all living organisms, the cell is the basic unit of structure and function. - An organism's behavior is dependent on the overall behavior of individual cells. - Within cells, energy movement (metabolism and biochemistry) occurs. - Cells contain DNA that is primarily contained in the chromosome and the cell's RNA. - In chemical composition, all of the cells are the same in organisms of similar species.
So, the answer is ‘(d) German Biologists’.

Note:
- While Rudolf Virchow also contributed to the theory. He is not known for his attributions to cellular theory.
- In modern cell theory, the mechanism of crystallization is no longer accepted.
- Robert Remak, Rudolf Virchow, and Albert Kolliker rejected Schleiden's theory of free cell formation by crystallization in the 1850s. In 1855, Rudolf Virchow applied the third concept to the theory of cells.