The correct answer among the choices provided is option A. Lung capillaries are responsible for exchanging carbon dioxide for oxygen from the air. Blood that comes from the heart gets oxygen from the alveoli. The carbon dioxide in the blood goes into the alveoli at the same time.
I can’t give you a specific answer because I’m not sure what your lab is. However, an independent variable is the variable that is changed, the dependent variable is the variable that is affected by the change, and the constant variables are those which remain the same throughout the entire experiment.
I believe the order is...
Producers
Primary Consumers
Secondary Consumers
Tertiary Consumers
I hope this helps!
