How are organs defined in biological structure?

The definition of organs in biological structure is indeed tied to tissues being arranged to perform specific functions. An organ is composed of different types of tissues that work collaboratively to carry out a particular activity that is essential for the organism's survival. For example, the heart consists of muscle tissue to pump blood, connective tissue to support its structure, and nervous tissue to regulate its activity.

The choice that defines organs as "groups of similar cells" describes a tissue rather than an organ since tissues consist of similar cells working together for a common purpose. Similarly, the option that mentions "cells grouped without a specific function" does not reflect the organized functional structure that characterizes an organ; rather, it points to a lack of organization necessary for function. Lastly, referring to "embedded structures in tissue" lacks clarity and does not accurately describe how organs are formed or function. Therefore, the arrangement of tissues performing specific roles defines organs clearly and correctly.