Answer: C) Hydrogen Explanation: Hydrogen is the common element to all Acids. But every element which contains Hydrogen is not an Acid. Most of the acids also contain Oxygen.

Answer: C) 5% Explanation: Let 'R%' be the rate of interest From the given data, 25202400 = 1 + R10041 + R1003⇒1 + R100 = 6360⇒R = 5   Hence, the rate of interest R = 5% per annum.

Answer: D) Checks and Balances Explanation: A procedure or method called Checks and Balances stops one branch of government from becoming too powerful. In the United States, there are three branches of government: The Executive, Legislative, and Judicial.   Each has its own responsibilities and at the same time they work together to make the country run smoothly and to assure that the rights of citizens are not ignored or disallowed.   There is a clear separation of powers between them.   Checks and Balances limit the power within each branch.   Each branch can stop and/or override processes within other branches in manners that are outlined in federal laws, regulations, and the constitution.   This way, their powers are balanced because the branches of government have the responsibility to check each other.