Gastrulation results in the formation of a(n)
A. trophoblast.
B. embryo.
C. morula.
D. umbilical cord.
E. blastocyst.
Answer: B
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An adult human kidney typically contains ________ renal pyramid(s).
A. 16 to 24 B. 8 to 15 C. 1 D. 30 to 40 E. 2 to 5
The portion of a lever between the fulcrum and the point where a force is applied by the muscle is called the ____
a. fulcrum angle b. velocity c. power arm d. load arm e. interactive unit
Answer the following questions true (T) or false (F)
1. The placenta, a temporary organ that is shed after the infant is born, is the site of exchange of oxygen, nutrients, and waste between the mother and fetus. 2. During month 4 of prenatal development, the fetus turns upside down in the vertex position. 3. The ductus arteriosus is a fetal vascular shunt that allows blood to flow from the pulmonary trunk directly into the aorta.
Which of the following is not true of the SA node?
A) It is located at the junction of the superior vena cava and right atrium near the superior end of the sulcus terminalis. B) It is the pacemaker of the heart. C) It sends impulses directly to the interventricular bundle of subendocardial branches (fibers). D) It receives sympathetic impulses from the first five to six thoracic segments that accelerate its basal rate. E) It receives parasympathetic impulses from the vagus nerve that decrease its basal rate.