What you meant must be the adaptive advantage of the frogs' lungs. Frogs are considered as amphibians wherein the have this unique ability to reside either on land or in water. Their specialised lungs could be responsible to these which makes them capable of breathing oxygen in water and land.
Well you know sometimes you see a lot of small bridges that will have weight limit signs. I believe this is really for safety precautions. Keyword: SMALL bridge -
Due to some bridges being small, the materials and strength of the bridge may not can withstand a certain weight. The contents of the vehicle, axels, and wheels, all add to that weight. So there is a very good reason for that to matter.
I hope my somewhat, tied together answer provides just the information you need!
~Brooke❤️
Blood first enters the heart's right atrium. A muscle contraction forces the blood through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood is forced through the pulmonary semilunar valve into the pulmonary artery. Then it travels to the lungs