Final answer:
Organ systems are groups of organs that work together to carry out complex functions.
Step-by-step explanation:
Organs systems are All of the answers are correct. Organ systems are groups of organs that work together to carry out complex functions. They are anatomical units with related functions, formed by two or more organs, often large enough to be studied without magnification, and interdependent on each other. For example, the circulatory system includes the heart, blood vessels, and blood, and it works together with other systems like the respiratory system.