Answer:
Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls - allow gases to pass through. Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.
Answer:
hope it helps you to please mark me brainliest
I wish I could help but I speak english.
Answer:
A chromosome is tightly compacted DNA, and a gene is a section of DNA that is used to code for certain characteristics.
D. Muscles are the only tissue in the body that can contract, and are responsible for all movement.
