The "lub" sound of the "lub-dub" heartbeat is due to what?

A. the right atrium contracting
B. the closing of the semilunar valves
C. the closing of the AV valves
D. the relaxation of both atria
E. the left atrium contracting


Answer: C

Biology & Microbiology

You might also like to view...

Which sterilization technique involves cutting the vas deferens on each side to prevent sperm from leaving the body?

A) hysterectomy B) tubal ligation C) vasectomy D) testicular deactivation

Biology & Microbiology

When the liver malfunctions and there is an abnormally large amount of bilirubin in the blood it can cause

A. the rolling stones. B. gallstones. C. cirrhosis of the liver. D. jaundice. E. kidney stones.

Biology & Microbiology

Which of the following is an example of a postzygotic reproductive barrier

What will be an ideal response?

Biology & Microbiology

Collection of microtubules that assist in the orderly distribution of chromosomes during cell division.

What will be an ideal response?

Biology & Microbiology