The base of the heart is found at approximately the level of the ...

[rosent76]

The base of the heart is found at approximately the level of the _____ rib(s).
 
  a. first
  b. second
  c. fourth
  d. fifth and sixth

Question 2

Rapid ejection of blood from the ventricular chambers of the heart occurs because the _____ and _____ valves open.
 
  a. pulmonic; aortic
  b. tricuspid; mitral
  c. pulmonic; mitral
  d. tricuspid; aortic

[anoriega3]

Answer to Question 1

B
The base of the heart is its upper portion and is formed mainly by the left atrium, with a small amount of right atrium. It lies at approximately the level of the second rib, immediately in front of the esophagus and descending aorta.

Answer to Question 2

A
When the ventricles contract, the pulmonic and aortic valves open, allowing blood to flow out of the ventricles.