Which of the following is a key characteristic of the Mesozoic era?

During the Mesozoic era, which is often referred to as the "Age of Reptiles," one of the most defining characteristics is indeed the dominance of dinosaurs. This era spanned from approximately 252 to 66 million years ago and is divided into three periods: the Triassic, Jurassic, and Cretaceous. Dinosaurs evolved and diversified during this time, becoming the dominant terrestrial vertebrates.

The presence of diverse dinosaur species led to various adaptive radiations and ecological niches being filled, which significantly impacted ecosystems. These reptiles exhibited immense variation in size, shape, and lifestyle, ranging from small, feathered creatures to massive long-necked herbivores and fearsome predators. The dominance of dinosaurs is a hallmark of the Mesozoic era, marking a significant evolutionary phase in the history of life on Earth.

While the other options do represent significant developments during the Mesozoic, they do not define the era as fundamentally as the prominence of dinosaurs does. For instance, mammals did develop during this time, but they were relatively small and not dominant compared to dinosaurs. Flowering plants did appear in the Cretaceous period, but they were not the primary feature of the era. The emergence of reptiles is a broader evolutionary