the same kind of cells working together. different systems working together. the same kind of organs forming a system. different organs performing a function.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Heart muscle is best described as
Possibilities:
- the same kind of cells working together.
- different systems working together.
- the same kind of organs forming a system.
- different organs performing a function.

the same kind of cells working together.