Answer:
hill is a natural landform that extends above the surrounding terrain whereas a mountain is a large natural landform that extends above the surrounding terrain, usually forming a peak.
Each era is subdivided into a number of periods. The periods of the Cenozoic, the present era, are further divided into epochs. Many divisions of the geologic time scale are based on events in Earth's geologic history. Some divisions are based entirely on the fossil record.
Yes, Vietnam is a Southeast Asian country
