Extreme temperatures , climate change stunts plant growth and makes it difficult for plants to thrive and grow (:
The answer is choice a. Peter the great wanted to westernize, or europeanize Russia.
The power of the Executive Branch is vested in the President of the United States, who also acts as head of state and Commander-in-Chief of the armed forces.
The possible rewards were plenty, both material and immaterial. A person who would discover something could become rich from finding things and taking them for the King, and be rewarded for it. The immaterial things would be fame, or things like knight hood, or they could become nobles which would also entice fortune besides fame. They would be celebrated forever as discoverers, and many other things.