Existing landforms are modified by destructive forces, perhaps even eroded away by water, wind, ice, and gravity. Beneath the oceans, volcanic activity forms new seafloor while old seafloor is destroyed at the trenches.
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm), yet short, vein that receives venous return from the upper half of the body, above the diaphragm.
Answer:
a
Explanation:
all organism is made of cell.they are the basic structursl unit of life.