There are many of them but the most common are:
1.) Photosynthesis
2.) Solar Energy
3.)Thermochemical Reactions
The answer would be the availability of new farming land in the west, while back east, most of their land had already been taken.
Answer:
the most applicable answers are,
*Russia's economy was based on subsistence farming.
*The government of Russia was an autocratic monarchy
*The Russian tsar used the secret police to enforce his will.
Explanation:
It is simple to say that the life in Russia around the 1900s was extremely difficult and dangerous because of poverty and civil conflicts.
