The small test - "Galaxy" 1) How many galaxies are the since universe? a) Hundreds b) Millions c) Billions 2) How many kilometers is an astronomical unit? a) 150 million b) 170 million c) 180 million 3) How many kilometers is a light-year? a) 7,46 trillion b) 8,46 trillion c) 9,46 trillion 4) Which planet is closes to the sun? a) Mercury b) Venus c) Mars​