Question

Which of these is a multicellular organism?
A. Amoeba
B. Paramecium
C. Human beings
D. None of the above

Answer 1

Multicellular organisms are organisms which are made up of more than one type of cells and each cell present performs the different function in the body. Cellularity is one of the important criteria in the classification of the organisms.

Complete step by step answer: First of all we will discuss what is a cell?
We know that the cell is defined as the functional and the structural unit of life. It is called a structural unit because the combination of cells leads to the formation of tissue which forms the organs and organ system of an organism and it is considered as the functional unit because cells perform basic to major functions in the body.
As discussed above, cellularity is one of main criteria in classifying the organisms.
On the basis of number of cells, the organisms are divided into two groups:
Unicellular
Multicellular
Unicellular organisms are defined as the ones with the single cell in the body.
Multicellular organisms are defined as the one having more than one type of cells in the body.
Unicellular organisms are also known as prokaryotes and multicellular organisms are known as eukaryotes.
Now we will discuss about each option specifically:
Amoeba: It is a parasitic organism which belongs to the category prokaryotes and possesses only a single cell in its body.
Paramecium: It is also a parasitic organism in the category of prokaryotes having a single cell in the body.
Human beings: they are the higher organism having multiple cells in the body. Each has its different function depending upon its location.
Thus the correct option is C.

Note: There are certain cells in the body that do not have the replicative property such as neurons present in the brain and some cells of the body do not have nucleus such as RBC’s. They are the oxygen carrying cells lacking nucleus.