Or the first question it is B and for the second question it is D and for the 3rd question it is A
Answer:
D. Archimedes
Explanation:
Archimedes came up with the Archimedes Priciple, or physical law of buoyancy.
Answer:
d. a theory.
Explanation:
A set of logically interrelated statements that attempts to describe, explain, and (occasionally) predict social events is known as a theory.
A theory is a body of systematized ideas that is formulated with the intention of explaining concepts and justifying certain courses of action.
In certain cases such as research, theories can be used to predict other variables. It can be said to be a body of generalized thought or belief that can be learnt and thought, as the set of principles that apply to a particular item concept or event.
The correct answer is the plow. When the plow was invented agriculture was made much easier which enabled people to settle around and make surplus of food. This enabled them to trade with others and increase the size of the cities and the rest is history.