Answer
a.
Work Step by Step
A group of similar cells working together form a tissue. A group of different tissues working together form an organ. A group of organs working together to perform a specific function is an organ system.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.