Which allowed scientists to determine that earth was at least 4.3 billion years old?

In a the people elect the legislature, and the legislature chooses the head of government. question 5 options: parliamentary democracy communist state presidential democracy autocratic state

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?

All of these are describing which georgia company