heys, i finished a whole chapter but got stuck on these questions
1.The human body can produce 2.5 million blood cells per second. If a person donates 500 mL of blood, how long will it take to replace the red blood cells if a litre of blood contains 5 × 10^12 red blood cells?
2.The Sun is approximately 1.5 × 108 km from Earth and a comet is approximately
3 × 106 km from Earth. How many times further from Earth than the comet is the Sun?