Climate change threatens the air you breathe
I believe its carbohydrates?
I am pretty sure the answer is A but i'm not sure
Answer:
Simple organisms, such as theamoeba and earthworm, have a moist, permeable external surface. Oxygencan pass into them through this surface by diffusion. A large surface area is needed for effective gas exchange - so larger, more complex, organisms have special organs such as gills and lungs.
Explanation:
