Question

Cell arises from the pre-existing cell was stated by
A. Haeckel
B. Virchow
C. Hooke
D. Schleiden

Answer 1

Hint: Since no living organism can live without being cellular, cells may be considered as a basic unit of life. A single cell helps at the beginning of life. Organisms may be unicellular or made up of a single cell and multicellular or made up of many cells. While most bacteria are unicellular, higher plants and animals are multicellular.

Complete answer:
-Hooke observed the first cells from an organism and this observation led to the cell theory. The cell theory is based on the operations of scientific methodologies. Observation, hypothesis, formulation of theory, and modifications were involved while stating the cell theory.
-A German botanist, Matthias Schleiden initiated the observation by examining a large number of plant tissues. The fact that all plants were made up of one or more kinds of cells was the first observation made by him.
-A German zoologist, Schwann dedicated himself to the study of animal tissues including embryo development. It was observed by him that animals did not have a cell wall. A membrane covers them instead. Hence, a cell was defined by Schwann as a membrane-enclosed structure that contains a nucleus.
-Schleiden and Schwann formulated the cell theory by discussing their observations. According to the cell theory, it was stated that cells form the basis of the structure and function of organisms.
-In 1985, Rudolf Virchow made the observation that the division of pre-existing cells leads to the development of new cells. Louis Pasteur proved that one life originated from another life. Then, Haeckel concluded that the nucleus is the place of storage and transmission of hereditary material.
Thus, the correct option is B, i.e., Virchow.

Note: Thus, the cell theory states the following facts:
a. Cells and their products are the main components of all living beings. Each cell has a protoplasm with a nucleus. A plasma membrane is present which may or may not have a cell wall.
b. Chemically and physiologically all cells are alike.
c. Activities of an organism can be defined as the summation of the activities and the interactions of its constituent cells.