The embryonic membrane that completely encloses the embryo in a watery sac is the ________.
A. ectodermal sac
B. chorion
C. allantois
D. yolk sac
E. amnion
Answer: E
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A muscle tissue with multinucleated cells would be classified as ___________ muscle.
Fill in the blank(s) with the appropriate word(s).
Which of the following statements about the refractory period of a membrane is TRUE?
A. The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials. B. The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential. C. The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that is undergoing an action potential, no matter how great the strength of the stimulus. D. The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential if a stronger than normal stimulus is applied. E. All of the answer choices are correct.
Answer the following statements true (T) or false (F)
1. The parathyroid gland is an endocrine gland found in the neck. 2. The hypothalamus is an endocrine gland found in the skull. 3. The pancreas is an endocrine gland found in the abdominal cavity. 4. The cardiovascular system includes the heart and blood vessels. 5. The primary function of the cardiovascular system is the regulation of body temperature.
a base _______________ is a consecutive sequence of three DNA nucleotides that codes for one amino acid.
Fill in the blank(s) with the appropriate word(s).