Cells with similar markers stick together and function as
a. systems
b. organs
c. organisms
d. tissues

The correct answer is D) Tissues.

There are five level of organisation present in the living organisms. These are cell, tissue, organ, organ system, an organism. Thus, tissue is one of the levels of organisation of living organisms.

Cells which are of similar types and perform the similar function are clustered together and form tissue.

Example- Epithelial tissue. It provides protection to the body as it is present in the external and internal lining of body. All the cells present in this tissue are called as epithelial cells. These cells are linked together by tight junctions.