Question

The organism made up of only a single cell is known as
A)Unicellular
B)Acellular
C)Multicellular
D)None of the above

Answer 1

Hint: Microorganisms are defined as the organisms that cannot be seen with naked eyes but are only visible under microscope. They can be both unicellular and multicellular. The study of microorganisms is called microbiology

Complete answer:
There are 5 types of microorganisms that includes:
1.Bacteria and archaea bacteria
2.Fungi
3.Algae - Protozoa
4.Viruses.

Now let us find solution from given options :
Unicellular organism- A unicellular organism is termed as an organism that is composed up of one single cell.
All the metabolic and physiological processes that are essential for the survival of that organism is performed by a single cell. They are typically microscopic and possess a small size.
Many unicellular organisms can survive and thrive in extreme climates like ice caps, hot springs, frozen tundra, human gut, ocean vents. These are termed as extremophiles

Acellular : the organisms those do not possess cells are termed as acellular. Viruses are considered to be acellular.
Multicellular organisms- Organisms that show the presence of more than one cell are called multicellular organisms.
They vary from microscopic fungi to macroscopic human beings.

In multicellular organisms, basic bodily functions for instance metabolism, circulation, excretion, reproduction, digestion, etc. are divided into organs and organ systems that are made of structurally and functionally identical cells.
Examples of multicellular Organisms include fungi, plants, fish, bats, birds, apes, human beings.

Hence, the correct answer is option (A)

Note: There are many much broader classifications of multicellular organisms on the basis of structure and function of their cells. We study and classify them and their names under Taxonomy.