Calcium levels in the body are maintained by hormones. If the blood calcium level rises above a set point, calcitonin is secreted by the thyroid gland and sets into motion responses to lower the blood calcium back to the set point
If the blood calcium level falls below a set point, the parathyroid gland secretes parathyroid hormone that sets into motion responses to raise the blood calcium. These homeostatic responses are examples of A) positive feedback.
B) effectors.
C) sensors.
D) negative feedback.
D
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Which of the following defines the benthic realm?
a. The area of the ocean that is considered open water. b. The area of the ocean into which no light can penetrate. c. The area that extends along the ocean bottom along the shoreline to the deepest parts of the ocean floor. d. The area of the ocean between high and low tide that is the oceanic region closest to land.
Secretions from the bulbourethral gland lubricate and cleanse the urethra of urine residue prior to the entry of sperm
Indicate whether the statement is true or false
Identify two different types of mating systems and list the advantages and disadvantages of each. What will be an ideal response?
In the logistic growth curve formula, when N is very large, (K-N)/N is almost equal to 0, which results in
A. the population going extinct. B. the population growth slowing to zero. C. the population growing as fast as it can, or r(N). D. the population exceeding carrying capacity; more are dying due to starvation than are born. E. You can't tell without knowing the value of r (rate of reproduction).