Answer:
1.The constellations best seen in March are Cancer, Canis Minor, Carina, Lynx, Pyxis, Vela and Volans. Cancer, Canis Minor and Lynx.
—The constellations best seen in June are Boötes, Libra, Lupus and Ursa Minor. Boötes and Ursa Minor.
—The constellations best seen in September are Capricornus, Cygnus, Delphinus, Equuleus, Indus, Microscopium and Vulpecula.
—The constellations best seen in December are Aries, Eridanus, Fornax, Horologium, Perseus and Triangulum. Perseus, Triangulum and Aries.
2.Because Earth is simultaneously revolving around the sun as it rotates on its axis, constellations in different parts of the sky are only visible during certain seasons.
3.It is a case of apparent motion. In the case of the earth and the constellations the earth rotates, with us on it, from west to east.
4.Constellations are useful because they help stargazers and astronomers recognise specific stars in the night sky. Today, constellations are less important than they were in Ancient History.
—Constellations were also used for navigation and to help sailors travel across oceans.
