1. Why does the human body reject transplanted organs from pigs?
A. They are too dirty.
B. Pigs have different blood types
C. A sugar on the surface of the pig's cells is unique to pigs.
D. They are the wrong size.

C. A sugar on the surface of the pig's cells is unique to pigs.

Explanation:

This rapid rejection occurs when human antibodies attach to sugar molecules on the surface of the transplanted pig organ's cells.

allowed for the prediction of the properties of missing elements.

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.