Inventors and Scientific Discoveries

The world's first car was invented in 1769 by Nicholas Joseph Cugnot.

The cell theory was jointly put forward by Schleiden and Schwann in their paper, "Microscope investigations on the similarity of structure and growth of animals and plants''. The theory stated that 'the cell are the units of both structure and function of the organisms'. 

Cell theory is a scientific theory,  which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction. Cell theory was eventually formulated in 1838. This is usually credited to Mattias Schleiden and Theodor Schwann. The cell theory, was further expanded by Virchow. Cell theory, has become the foundation of biology and is the most widely accepted explanation of the function of cells.
So, the correct answer is option D.

Cell theory was proposed by a German botanist, Matthias Schleiden and English zoologist, Theodor Schwann in the year 1839. The cell theory states
1) Cells are the building blocks of living organisms.
2) All living organisms are composed of cells and a cell is the basic structural and functional unit
3) All cells arise from pre-existing cells.

Cell theory was proposed by a German botanist, Matthias Schleiden and English zoologist, Theodor Schwann in the year 1839. Cell theory was considered as most acceptable theory which, elucidated the functioning of cell. The cell theory includes the following points -
1) All living things are made up of cells.
2) The cell is the smallest living thing that can perform all the functions of life.   
3) All cells must come from pre-existing cells.
So, the correct answer is option D.

Cell theory was proposed by a German botanist, Matthias Schleiden and English zoologist, Theodor Schwann in the year 1839. The cell theory states 
1) Cells are the building blocks of living organisms.
2) All living organisms are composed of cells and a cell is the basic structural and functional unit
Later on, Rudolf Virchow added a new point in cell theory that 'all cells arise from pre-existing cells'.
So, the correct answer is option B.

The term hypothesis means a proposition or a set of propositions set forth as an explanation for the occurrence of some specific phenomenon. In this case, the phenomenon was smallest constituent entity of living organisms. In 1838, German Botanist Matthias Schleiden found that all plant tissues are made up of cells which have essentially similar structure. German zoologist Theodor Schwann, 1839, working independently observed that animal cells do not have cell wall but are otherwise similar among themselves. Thus, the original idea of both the workers was a hypothesis based on their observation which had to be experimentally verified by other workers.

Schleiden was the son of a well-to-do municipal physician of Hamburg. He first studied law at the University of Hamburg from 1824 to 1827 and obtained a doctorate. He subsequently practiced law in Hamburg, but was unhappy with his career choice and choose to develop his hobby of botany into a full-time pursuit.

In 1838, Matthias Jakob Schleiden, who is a German botanist, was born in Hamburg located in Germany. He was a co-founder of the cell theory. He hypothesized that the body of plants and animals are composed of cells and product of cells.

• Cell theory was proposed by a German botanist, Matthias Schleiden 1838 and English zoologist, Theodor Schwann in the year 1839. Cell theory was considered as the most acceptable theory which, elucidated the functioning of a cell.
•  The cell theory includes the following points -

1) All living things are made up of cells.
2) The cell is the smallest living thing that can perform all the functions of life.   
Later on, in the year 1855, Rudolf Virchow added a new point in cell theory that all cells must come from pre-existing cells, which was also known as "Omnis cellula e cellula".

Robert Brown discovered the cell is false because cells were first discovered by Robert Hooke.

In 1855 Rudolf Virchow, after an exciting study of the growth of cells in human tissues, stated clearly that all arise only by the division of pre-existing cells. Virchow's famous statement of this concept, 'Omnis cellula e cellula', completed the cell theory. 

Theodor Schwann and Matthias Jakob Schleiden proposed the cell theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction.

Matthias Jakob Schleiden, a German botanist who gave the cell theory, proposes that all plant tissues are composed of cells and that cells are the basic building blocks of all plants and generalized as all the tissue is made up of individual cells.