The supreme court's decision in the case marbury v. madison is important because it allowed the supreme court to overrule an unconstitutional law it allowed the supreme court to hear cases on appeal from a lower court it allowed the president to overrule an unconstitutional law it allowed the supreme court to hear cases in its original jurisdiction

It allowed the Supreme Court to overrule an unconstitutional law.

Explanation:

United States President John Adams along with the Congress approved the Judiciary Act of 1801, and appointed new circuit judges and justices of the peace before he left office (one of this judges was William Marbury) and when President Thomas Jefferson took office, he declared that this commissions were void, and instructed the new Secretary o State James Madison not to deliver them. One of this commissions included Marbury, and after he petitioned Madison to deliver his commission with negative answers, he took his case to court. Although the court decided that Madison's refusal to deliver the commission was illegal, it held that the Judiciary Act of 1789 which allowed Madison to take his case to the Supreme Court was unconstitutional.

Chief of Justice John Marshall then established the power to declare a law unconstitutional under the principle of judicial review.  

the answer is b your welcome : )

in 1803 the louisiana purchase took place, doubling the size of the country. by 1840 almost 7 million americans had migrated westward in hopes of securing land and being prosperous. the belief that settlers were destined to expand to the west is often referred to as manifest destiny.

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