They do not have external ears like us. but they do have ear holes located directly behind their eyes. frogs ear holes are covered with thin tympanic membranes or the eardrums that protect the inner ear cavity.
Clay because it’s a mixture of dirt and runoff/water
Small intestine is modified due to the presence of micro villi which has ability to increase it's size
Pollution or Carbon Dioxide
I believe, for the artery, they have, an open, circular lumen an a thick media
Veins on the other hand, have somewhat collapsed lumen and a thinner media. Arteries are blood vessels that carry blood out of the heart to other parts of the body, all arteries carry oxygenated blood except the pulmonary artery which carries deoxygenated blood from the heart to the lungs. Veins carry blood from other body parts to the heart, all veins carry deoxygenated blood except the pulmonary vein which caries oxygenated blood from the lungs to the heart.
