A blastocyst is
A) an extraembryonic membrane that forms blood vessels.
B) a solid ball of cells.
C) a hollow ball of cells.
D) a portion of the placenta.
E) the membrane that forms the urinary bladder.
C) a hollow ball of cells.
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How does the reproductive system contribute to osteoporosis?
A. Calcium ions released from the bones are excreted. B. Immune cells resist infections and release chemicals that promote tissue repair. C. Decreased estrogen levels following menopause contribute to the disease. D. Lack of exposure to sunlight reduces vitamin D production and decreases calcium absorption. E. Excessive smoking lowers estrogen levels, which increases bone loss.
Which of the following is a type of cartilage?
A. Dense B. Areolar C. Spongy D. Elastic E. Reticular
A neuron is receiving a stimulus which gets stronger and stronger. The result is
A. amplitude of the action potential increases. B. duration of the action potential increases. C. frequency of occurrence of action potentials increases. D. resonance of action potentials increases. E. height of the action potentials increases.
A protective function of the respiratory system would be
A. altering blood pH by changing blood CO2 levels. B. olfaction by drawing molecules into the nasal cavity. C. producing ACE which helps regulate blood pressure. D. preventing microorganisms from entering the body.