Explanation:

The 73rd Constitutional Amendment added Part IX titled “The Panchayats” to the Constitution.

• Basic unit of democratic system-Gram Sabhas (villages) comprising all the adult members registered as voters. 
• Three-tier system of panchayats at village, intermediate block/taluk/Mandal and district levels except in States with population is below 20 lakhs (Article 243B).
• Seats at all levels to be filled by direct elections (Article 243C (2)).

Three-tier system of panchayats at village, intermediate block/taluk/Mandal and district levels except in States with population is below 20 lakhs (Article 243B).

• Seats at all levels to be filled by direct elections Article 243C (2).

Seats reserved for Scheduled Castes (SCs) and Scheduled Tribes (STs) and the chairpersons of the Panchayats at all levels also shall be reserved for SCs and STs in proportion to their population.

• One-third of the total number of seats to be reserved for women.
• One third of the seats reserved for SCs and STs are also reserved for women.

Hence only statement 2nd is correct.