An investigation of Russian imperial methods of political control reveals which of the following?

The tsar had to repeatedly work to remove all people who seemed to be obstacles to his rule.
The tsar was head of the empire and the most powerful, but he had to work with others to achieve political control.
The yasak tribute system was a very ineffective method of political control because it did not benefit the empire.
The church was the most important fixture in Russian life, and people followed it more than the tsar.

The first two options are correct:

1. The tsar had to repeatedly work to remove all people who seemed to be obstacles to his rule. This indicates that the tsar faced challenges from individuals who posed a threat to his authority and had to take measures to remove them.

2. The tsar was head of the empire and the most powerful, but he had to work with others to achieve political control. This suggests that although the tsar held significant power, he still needed to collaborate with other individuals or groups in order to maintain political control.

The third option is incorrect:

3. The yasak tribute system was a very ineffective method of political control because it did not benefit the empire. This statement is not supported by the information given in the question. The yasak tribute system was a system of taxation imposed on indigenous peoples in Siberia, and while it may have had drawbacks or limitations, it is not mentioned that it was ineffective or did not benefit the empire.

The fourth option is also incorrect:

4. The church was the most important fixture in Russian life, and people followed it more than the tsar. This statement is not supported by the information given in the question. While the church may have held significant influence in Russian society, it is not mentioned that it was more important than the tsar or that people followed it more than the tsar.