Answer: B

Statement 1 is correct. The news explicitly states Indian astronomers discovered Alakshnanda, an ancient spiral galaxy, using GMRT. Statement 2 is correct. The discovery challenges current models suggesting spiral galaxies formed much later. Statement 3 is incorrect. While spiral galaxies have a central bulge and arms, the arms are typically regions of active star formation, containing younger, blue stars, along with gas and dust. The central bulge tends to have older, redder stars.

Answer: C

Statement A is incorrect. GMRT is a radio telescope, not designed for gamma-ray or X-ray astronomy. Statement B is incorrect. GMRT is located near Pune, Maharashtra, and is operated by the National Centre for Radio Astrophysics (NCRA) of the Tata Institute of Fundamental Research (TIFR), not ISRO. Statement C is correct. GMRT is a radio telescope, operating in metre wavelengths, making it ideal for studying radio emissions from pulsars, quasars, and distant galaxies, including those from the early universe. Statement D is incorrect. Radio telescopes detect radio waves, not visible light. Their advantage lies in observing phenomena that emit radio waves, penetrating dust clouds, and studying redshifted signals from the early universe, not in resolving visible light details.

Answer: B

Statement 1 is correct. The cosmic dark ages occurred after recombination (when electrons and protons formed neutral hydrogen) but before the first stars and quasars reionized the universe. Statement 2 is incorrect. Current cosmological models, including those challenged by Alakshnanda, heavily rely on dark matter halos as the gravitational scaffolding for galaxy formation. The early formation of a spiral galaxy like Alakshnanda might challenge the timeline of dark matter halo assembly or the efficiency of baryonic matter collapse within them, but it doesn't suggest independence from dark matter. Dark matter is still considered crucial for galaxy formation. Statement 3 is correct. Redshift is a direct observational evidence for the expansion of the universe, as light from receding galaxies is stretched to longer (redder) wavelengths.

Answer: B

Statement 1 is correct. The news explicitly states Indian astronomers discovered Alakshnanda, an ancient spiral galaxy, using GMRT. Statement 2 is correct. The discovery challenges current models suggesting spiral galaxies formed much later. Statement 3 is incorrect. While spiral galaxies have a central bulge and arms, the arms are typically regions of active star formation, containing younger, blue stars, along with gas and dust. The central bulge tends to have older, redder stars.

Answer: C

Statement A is incorrect. GMRT is a radio telescope, not designed for gamma-ray or X-ray astronomy. Statement B is incorrect. GMRT is located near Pune, Maharashtra, and is operated by the National Centre for Radio Astrophysics (NCRA) of the Tata Institute of Fundamental Research (TIFR), not ISRO. Statement C is correct. GMRT is a radio telescope, operating in metre wavelengths, making it ideal for studying radio emissions from pulsars, quasars, and distant galaxies, including those from the early universe. Statement D is incorrect. Radio telescopes detect radio waves, not visible light. Their advantage lies in observing phenomena that emit radio waves, penetrating dust clouds, and studying redshifted signals from the early universe, not in resolving visible light details.

Answer: B

Statement 1 is correct. The cosmic dark ages occurred after recombination (when electrons and protons formed neutral hydrogen) but before the first stars and quasars reionized the universe. Statement 2 is incorrect. Current cosmological models, including those challenged by Alakshnanda, heavily rely on dark matter halos as the gravitational scaffolding for galaxy formation. The early formation of a spiral galaxy like Alakshnanda might challenge the timeline of dark matter halo assembly or the efficiency of baryonic matter collapse within them, but it doesn't suggest independence from dark matter. Dark matter is still considered crucial for galaxy formation. Statement 3 is correct. Redshift is a direct observational evidence for the expansion of the universe, as light from receding galaxies is stretched to longer (redder) wavelengths.