Question

“It is said that every multicellular organism has come from a single cell”. Which of the following statements can be related to this?
A. Every organism starts its life from a zygote, a single cell.
B. Cells divide to produce cells of their own kind and thus all the cells of the body come from pre-existing cells.
C. Both A and B
D. none.

Answer 1

Hint:Cell is the structural unit of every organism. All living organisms show cellular organization whether it is unicellular or multicellular. Unicellular organisms are bacteria and Protista. Fungi, Animalia, and all plants are multicellular. That’s why cells are called a structural and functional unit of all living organisms.

Complete answer:
As we know that every organism has a cell as its structural unit. The cell does all the important functions of life. One of the most important abilities of a cell is to divide. By cell division, a cell divides and produces two or more than two cells. Which are similar to the mother cell. So it can be said that cells divide to produce cells of their own kind and thus, all cells of the body come from pre-existing cells.
By division, from a single cell, a group of cells is made and then a multicellular organism is made. So it is clear that every multicellular animal has come from a single cell.
The cell that shows cell divisions and by cell divisions form a multicellular organism is actually a zygote. This zygotic cell is made by the fusion of two gametic cells. Zygote shows the earliest stage of development of any organism. So that’s why we can relate this as every organism starts its life from a single cell that is a zygote.

Therefore, the correct answer is option C) Both a and b.

Note: The concept that a cell divides and new cells are made by pre-existing cells, was given by scientist Rudolf Virchow in 1855. Two scientists said that all organisms are made by cells and their products. Later from these two concepts new cell theory was given in 1838.