Speed , Velocity , or Acceleration ? A bird flies 15 m/s southeast.

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

This is collection of data made by comparing objects in standard units. in science, the units are metric.