Explanation:

• Statement 1 is correct: The presiding officer of the Rajya Sabha is known as the Chairman. The Vice-President of India is the ex-officio Chairman of the Rajya Sabha. In this capacity, his powers and functions are similar to those of the Speaker of Lok Sabha. In this respect, he resembles the American vice president who also acts as the Chairman of the Senate–the Upper House of the American legislature. He acts as President when a vacancy occurs in the office of the President due to his resignation, impeachment, death or otherwise.
• Statement 2 is incorrect: The Vice-President, like President, elected by the method of indirect election. He is elected by the members of the Parliament (both elected and nominated). However, the electoral college doesn't include the members of the state legislative assemblies.
• Statement 3 is incorrect: Article 71 of the Constitution of India mentions that all the doubts and disputes arising out of or in connection with election of a President or Vice-President shall be inquired into and decided by the Supreme court whose decision shall be final. The election of a person as Vice-President cannot be challenged on the ground that the electoral college was incomplete.
• If the election of a person as VicePresident is declared void by the Supreme Court, acts done by him before the date of such declaration of the Supreme Court are not invalidated (i.e., they continue to remain in force).