The answer to your question is knowledge. Scientific knowledge is the information gathered by the systematic study of nature.
Climate is a consistent temperature and weather that usually changes little throughout the years. The answer should be A because this describes the general year-to-year weather.
One simple and easy way that scientists can accurately date fossils found is through the ground levels. When you take a big chunk out of the earth, you can see the changes in the texture in the "ground" Each "layer" represents a set of years. And as you get further and further into the ground, fossils become older and older.
Some of the animals present in Russia are tiger, leopard, snow leopard, Pallas's cat, grey wolf, dohl, brown bear, red squirrel, wild boar, saiga, Eurasian elk, walrus, Eurasian beaver, and many more.
