UPSC Prelims 2023 question on Cepheids Nebulae Pulsars

Statement by statement

Pair 1 – NOT CORRECTLY MATCHED: Cepheids, also called Cepheid Variables, are stars which brighten and dim periodically. This behavior allows them to be used as cosmic yardsticks out to distances of a few tens of millions of light-years — they are NOT giant clouds of dust and gas in space.

Pair 2 – NOT CORRECTLY MATCHED: Nebula is a giant cloud of dust and gas in space. Some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova. Other nebulae are regions where new stars are beginning to form — they are NOT stars which brighten and dim periodically.

Pair 3 – CORRECTLY MATCHED: Pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds. Neutron stars are formed when a massive star runs out of fuel and collapses.