Describe the pattern of fetal blood flow to and from the placenta
A) Deoxygenated blood flows from the fetus to the placenta through a pair of umbilical arteries, and oxygenated blood returns from the placenta in a single umbilical vein.
B) Deoxygenated blood flows from the fetus to the placenta through a pair of umbilical veins, and oxygenated blood returns from the placenta in a single umbilical artery.
C) Oxygenated blood flows from the fetus to the placenta through a pair of umbilical arteries, and deoxygenated blood returns from the placenta in a single umbilical vein.
D) Oxygenated blood flows from the fetus to the placenta through a pair of umbilical veins, and deoxygenated blood returns from the placenta in a single umbilical artery.
E) Deoxygenated blood flows from the fetus to the placenta through a single umbilical vein, and oxygenated blood returns from the placenta through a pair of umbilical arteries.
Answer: A
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Initially appendicitis manifests as diffuse pain in the periumbilical region and later as circumscribed pain in the right lower quadrant. Why?
A) Because the appendix swells with appendicitis so that it contacts both the anterior and posterior abdominal walls. B) Because the pain is first conveyed via vagal parasympathetic fibers and then by somatic fibers in the parietal peritoneum of the abdominal wall. C) Because the pain is first conveyed via sympathetic fibers that enter the spinal cord at the T10 level and then by somatic fibers in the parietal peritoneum of the abdominal wall. D) Because the appendix first irritates the subcostal nerve and then the ilioinguinal nerve. E) Because the most sensitive afferents of the appendix are those that are associated with the sympathetic fibers that enter the T10 level of the spinal cord, but later less sensitive afferents associated with the lower quadrant become activated.
Which of the following can contribute to the resultant linear velocity of a projectile at release?
A. tangential acceleration B. radial acceleration C. both A and B D. none of the above
A polar body biopsy is a type ofÂ
A. amniocentesis in which polar bodies are sampled from fluids surrounding the fetus. B. gene therapy in which a polar body is inserted into a zygote. C. chorionic villi sampling (CVS) in which villi of the polar body are tested. D. preimplantation genetic study in which a polar body is tested for genetic disorders.
Which of the following statements about DNA replication is TRUE?
The leading strand is replicated continuously, while the lagging strand is replicated discontinuously. The leading strand is replicated discontinuously, while the lagging strand is replicated continuously. Both the leading and lagging strands are replicated continuously. Both the leading and lagging strands are replicated discontinuously. Each of the leading and lagging strands is replicated both continuously and discontinuously.