One cubic millimeter (mm^3 ) of blood contains 7.0 x 10^6 red blood cells. How many red blood cells are in 1.0 L of blood? Recall that 1 mL = 1 cm^3 . 7.0 × 10^12 red blood cells7.0 × 10^18 red blood cells7.0 × 10^9 red blood cells7.0 × 10^7 red blood cells