Question

A Group of similar cells performing similar functions is called a/an
A.Organ
B.Tissue
C.Organ system
D.Organism

Answer 1

Hint: The multicellular organism, an organism consisting of several cells, is interconnected and autonomous to varying degrees. Cellular specialization and division of labor follow the growth of multicellular organisms; cells become effective in one phase and rely on other cells for the necessities of life.

Complete answer:
The organ is a collection of tissues that have been modified to a particular role in a living organism. In the higher species, the organs are actually grouped together for e.g. oesophagus, stomach, and intestine into organ systems together with associated glands are digestive system organs.

Tissues are classes with a shared feature with identical cells. An organ is a structure that is composed of at least two or more types of tissue and performs a particular collection of body functions. An organ system is named from several organs working together to achieve a shared goal.
An organ system is a series of organs working together to perform a certain function in an organism's body. Most animals and plants have organs that are self-contained tissue groups, such as the heart, that work together to perform one function. In humans and other animals, many organ systems exist.
An organism is a living thing which has an organized structure, and is made of different types of organ systems.

Hence, the correct answer is option (B)

Note: In animals there are for basic types of tissues:
Connective tissue, 2. Epithelial tissue 3. Muscle tissue, and 4. Nervous tissue.
Connective tissue is responsible for support and binding. Epithelial tissue is responsible for providing covering of the organs internally a well as externally.