The primary pacemaker of the heart is the

(a) bicuspid valve.
(b) tricuspid valve.
(c) aorta.
(d) sinoatrial node.


(d) sinoatrial node.

Biology & Microbiology

You might also like to view...

Most systemic mycoses are acquired from ________.

A. insect vectors B. inhaling spores C. puncture wounds D. All of the choices are correct.

Biology & Microbiology

FSH and LH are secreted by the:

a. hypothalamus b. ovaries c. anterior pituitary d. testes e. uterus

Biology & Microbiology

Water in the oceans tends to move in great currents from the:

a. north pole to the south pole b. equator to the poles c. poles to the equator d. south pole to the north pole e. equator to the poles and back again

Biology & Microbiology

When do eggs first develop in a woman?

A) prior to birth B) at puberty C) throughout her lifetime D) every 60 days

Biology & Microbiology