evolved during the Carboniferous Period.

Amphibians And Reptiles of The Carboniferous Period

During the Carboniferous, more and more species of tetrapods evolved. Some were early amphibians that began their lives in the water and later moved onto land. Some were early reptiles that developed leathery skin as they moved to the parts of land that were very dry.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation: