Which of the following is true of the contraction of the heart?
A) The muscle obtains the beat from the pacemaker region exclusively.
B) The ventricles contract first, followed by the atria.
C) Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers.
D) The contractions do not occur in any specific repeatable sequence each time.
E) None of the answers are correct.
C) Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers.
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Which of the following chromosomal abnormalities most severely affect a fetus?
A) Trisomy 21 B) Monosomy for a large autosome C) XXY D) XXX
___________ is the eye pigment that detects light in conjunctions with setting the body's biological clock
Fill in the blank(s) with correct word
The only lymphatic organ(s) with afferent lymphatic vessels is(are) the ________.
A. spleen B. red bone marrow C. tonsils D. lymph nodes E. thymus
Most membranes are composed of two or three tissue types. However, an example of an exception is the ________ membrane
A) cutaneous B) mucous C) synovial D) serous E) basement