When used as directed with other sun protection measures, broad spectrum sunscreen with an SPF of 15 or higher helps prevent sunburn and reduces the risk of early skin aging and skin cancer (melanoma and squamous cell carcinomas) associated with UV radiation. hope this helped lower the answers
I am sure that the answer is D
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.
