In terms of geological time scale, how long did the Mesozoic Era last?

The Mesozoic Era, often called the "Age of Reptiles," lasted for approximately 180 million years. It is subdivided into three distinct periods: the Triassic, Jurassic, and Cretaceous, which together span from about 252 million years ago to about 66 million years ago. This timeframe highlights significant geological and biological developments, including the rise of dinosaurs and the first appearances of mammals and birds.

The other options reflect different time spans relevant to other geological periods or eras but do not accurately represent the duration of the Mesozoic Era as a whole. For instance, the Mesozoic Era is longer than just 100 million or 65 million years, and while 250 million years is a significant duration, it extends beyond the actual length of the Mesozoic Era. Hence, the choice indicating approximately 180 million years correctly encapsulates the timespan of this crucial era in Earth's history.