Question

An organism made up of many cells is called a
A) Unicellular
B) Multicellular
C) Microorganisms
D) None of the above

Answer 1

Hint: Living organisms can be both prokaryotic and eukaryotic. They can be one-celled or multi-celled.

Complete Answer:
1) Unicellular organism- A unicellular organism is an organism that is made up of one single cell.
- All the metabolic and physiological processes necessary for the survival of that organism is performed by a single cell. They are typically microscopic.
- Many unicellular organisms can survive in extreme climates like ice caps, hot springs, frozen tundra, human gut, ocean vents. These are called extremophiles.
- Extremophiles are resistant to pH and temperature and can live in extreme climatic conditions, unlike multicellular organisms. However not all unicellular life forms are extremophiles, a lot of them just survive in the narrow range of temperature, pressure, and pH like other multi-celled organisms.
- Examples of unicellular organisms are Amoeba, bacteria, diatoms, euglena, paramecium, planktons, etc are unicellular organisms.

2) Multicellular organisms- Organisms that have more than one cell are called multicellular organisms.
- They range from microscopic fungi to macroscopic human beings.
- The cells that make up the organism have specialized functions and I'm some cases specialized structures too.
- In multicellular organisms, basic bodily functions like 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 are fungi, plants, fish, bats, birds, apes, human beings.

3) Microorganisms- Microorganisms can be both unicellular and multicellular. These are organisms that cannot be seen by the naked eye but can only be perceived with the help of a microscope.
There are many 5 types of microorganisms,
- Bacteria and archaea bacteria
- Fungi
- Algae
- Protozoa
- Viruses.
Hence, an organism made up of many cells is called a multicellular organism.

The correct answer is option C.

Note: There are further broader classifications of multicellular organisms based on the structure and function of their cells. We study the classifications and their names under Taxonomy.