Over the centuries, much has changed. At the beginning of the 20th century, Einstein described his theory of relativity, in 1953; Jonas Salk says he can find the polio vaccine, in 1990 the Internet was invented ... But what about the changes taking place over a longer period of time, for example, millions of years?
Today I will try to answer the question: can we survive 2.5 million years ago. First let's look at the environment. 2.5 million years ago on Earth was the Pleistocene era. It started 2,600,000 years ago and ended 11,700 years ago. During this period, most of the glacial periods occur. At the height of this era, most of the water on Earth is in ice, and the average temperature on the planet is 5-10 degrees lower than it is now. It is a drier and colder planet.
During this period, you must associate with the representative of the species, which was one of the earliest ancestors. This is the question of an adept person (or homo habilis). These species are more like monkeys than humans, but they are already on the back foot and know how to make stone tools. However, fortunately for you, if you confront them, they will not attack you. The scientists' general view of these creatures comes to the fact that they are vegetarians.
And what about sickness? The basic idea of a disease that strikes a person is that it all comes to us from animals and, therefore, their growth is marked by a period when many animals are domesticated. Diseases such as tapeworms, microbial infections, tuberculosis and leprosy have appeared in the Pleistocene. Although the parasites that tolerate malaria existed 2.5 million years ago, but for humans they have almost no relationship. The disease problem begins with the development of agriculture. But, understandably, if one of the diseases will attack you, without drugs you will barely survive.