Explanation:

x Sounding rockets are one or two-stage solid propellant rockets used for probing the upper atmospheric regions and for space research. They also serve as easily affordable platforms to test or prove prototypes of new components or subsystems intended for use in launch vehicles and satellites. Hence, statement 1 is correct. x Unlike a satellite launch vehicle, a sounding rocket performs an observation mission during its flight in space before impact. It usually comprises one or two stages. When the experiment is completed, the rocket dives into the sea along with its observation instruments. Hence, statement 2 is correct. x The observation instruments are usually fixed to the rocket's nose fairing and covered by a nosecone like a pointed hat for protection from aerodynamic heating. When the rocket reaches a given altitude, timer-fixed functions start to open the nosecone, extend antennas, sometimes release test samples for observation, and conduct other tasks to prepare for the planned observation. The observation starts before the rocket reaches its maximum altitude and ends before it splashes down into the sea. x In 1963, Indian Space Programme started with the first sounding rocket launch from Thumba Equatorial Rocket Launching Station (TERLS), Kerala. Thumba was selected as it is close to the magnetic equator. In 1967, ISRO launched its own version of the sounding rocket - Rohini RH-75. In 1975, ISRO consolidated all sounding rocket activities under Rohini Sounding Rocket (RSR) Programme. x RH-200 (meteorology purpose) is one of three sounding rockets currently operational with ISRO, the other two being RH-300 Mk 2 and RH-560 Mk 2 (both for Aeronomy). o 200 in the name denotes rocket’s diameter in millimeters (mm). Rh-200 rocket used polyvinyl chloride (pvc) based propellant. In 2020, first, rh-200 used a new propellant based on hydroxyl-terminated polybutadiene (htpb). Hence, statement 3 is correct.