I think its most likely to be A,
Answer:
The respiratory system is a system in your body that is in charge of helping you breathe. the respiratory system is made up of airways, lungs, and blood vessels, these parts work together to get oxygen into your body. Our respiratory system is a vital system, as it lets us live and breathe.
Explanation:
Here you go, don't copy exactly
A homogeneous mixture (every part of the solution has the same properties) ,a heterogenous mixture (there are two or more phases present). one example of a mixture is air. >hope this helps..
