With reference to the above question, the increase in temperature in the troposphere especially within the last 75 years is primarily due to Group of answer choices the sun random fluctuations in temperature events unrelated to human activity increases in CO2 levels by humans burning fossil fuels

to human activity increases in CO2 levels by humans burning fossil fuels

Explanation:

In the last 75 years, human activities have increased considerably. These activities became increasingly dependent on the burning of fossil fuels, which released ever-increasing amounts of carbon dioxide into the atmosphere. Carbon dioxide, in turn, deteriorated the troposphere, allowing the sun's rays to warm the earth more and more.

doctrine that the us had the right to expand throughout north america.