When water travels across the surface of the Earth this process is called A. aquifers
B. oceans
C. glaciers
D. runoff

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.