Answer:
The US had the strongest Navy and dominated both the Pacific and the Atlantic uncontested; this didn't change throughout the Cold War, even though naval technologies changed a lot (nuclear subs, etc), and the USSR invested heavily in surface and submarine navies.
Explanation:
The principle of checks and balances refers to the system, in the American federal system, wherein each branch of government has responsibilities and obligations as it relates to the other branches of government.
The President, for one, is able to veto legislation from the Legislative Branch but a balance on that check is that the Legislative branch may override the Executive branch's veto.
The appropriate answer is B. steam boats could travel against the current on a river. This statement means that steam boats could travel upstream. The steam engine in steam boats allowed them to travel upstream possibly against a strong current. Sail boats rely on wind or the downstream flow of the water to move it from one location to the other. The invention of the steamboat revolutionised transportation of goods and people on large navigable rivers.
