Which of the following statements is true regarding the yolk sac in human embryos?
A. It gives rise to the digestive tract.
B. It is the source of the first blood cells.
C. It allows for gas exchange.
D. It allows for the passage of waste.
E. It is the major source of nutrients for the embryo.
B. It is the source of the first blood cells.
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Which of the following is not a connective tissue?
A. Blood B. Skeletal muscle C. Cartilage D. Areolar tissue E. Osseous tissue
Besides receptor density, a second factor influencing acuity is ____________________ inhibition
Fill in the blank(s) with correct word
Unmyelinated axons of the sympathetic division
A) may innervate effector organs. B) release NE. C) are postganglionic sympathetic fibers. D) may pass through the gray ramus. E) All of the answers are correct.
The thymus is where ________ mature and become functional immune cells.
A. pre-B cells B. macrophages C. null cells D. C cells E. pre-T cells