Question

Organisms that cannot be seen by naked eyes is called-
A. Cell
B. Microorganisms
C. Living things
D. All of the above

Answer 1

Hint: An organism can be considered as an organized body or system considered to be a living being. In an ecosystem, producers, consumers, and decomposers are considered as three types of organisms. An organism can either be a prokaryote or a eukaryote. Sometimes due to extreme conditions such as temperature and dryness, a cyst is formed by them which makes it very difficult to observe by naked eyes.

Complete answer:
- A cell is defined as the basic unit of life. These are structural, biological, and functional units of life. Having a diameter of 0.1 to 5.0 μm, prokaryotic cells are significantly smaller than eukaryotic cells, which have diameters in the range of 10 to 100 μm.
- Microorganisms are defined as the microscopic bodies which cannot be seen directly with the naked eye. These organisms are of the size in microns. The study which deals with microbes is known as microbiology. There are different types of microbes like bacteria, viruses, fungi, etc.

Microorganisms are divided into the following types:
- Bacteria, archaea, protozoans, algae, fungi, viruses, and multicellular animal parasites.
- Most microbes are around 1 micrometer in size.
- A thing is considered as a living thing if it has the properties to grow, move, breathe, and reproduce and also can express. After a certain point of growing, they die.
- For instance, human beings, plants, and animals are considered as living beings.
- So, Microorganisms cannot be seen with the naked eyes due to their very small size.

Hence, the correct answer is option (B).

Note: The organism can also be defined as an assembly of molecules into a stable whole that can be considered as living. A microscope is required to observe the microorganisms. A microscope is an instrument that is used to observe small objects. There are 3 types of a microscope - Compound, electron, and stereoscopic. These are used as per the requirement.