Question

Define Organ.

Answer 1

Hint: In biology, the basic and fundamental unit of life is a cell, whereas those cells divide to form the tissues, there are so many types of tissues present in the body, and these tissues of similar function are together to produce the organs, there are so many organs, and they all get together to form the organs system.

Complete answer:
An organ is a group of tissues, which have a similar function.
Tissues in the organs are different types, where they can be broadly categorized into Parenchyma, which is the tissue that is peculiar to the organ, but does not show any specialized function.
Whereas Stroma is the tissue found in the organs, with the functions regarding the structure, support, and connection.
For example, if there is an organ called a gland, in those organs, the tissue which produces the hormone is parenchyma, while nerves, blood vessels all are considered as the stroma.
Generally, the tissues which make up the organ are of the same origin, which means that they are from the same germ layer.
Organs are only present in the multicellular organisms, whereas in the single-cell organisms, instead of organs, organelles are present.
The organs of the same function are getting together to form the organ systems.
In the animals, the study of organs is called anatomy, while in the plants, it is called morphology.
Whereas in plants, there are also different types of organs such as vegetative organs and reproductive organs.

Note:
In society, there is a system for the donation of organs called as organ donation, in which the people with failing organs or deceased organs are transplanted with a healthy organ from the health persons, and not to reject these transplanted organs, the patient is under the immunosuppressive drugs.