Satellites in orbit around the earth a. produce data of poor quality because of earth's atmosphere. b. must return to earth to deliver the data that they collect. c. may contain telescopes and other instruments to study space. d. all of the above

helicase, i think thats it

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.