Flycatcher birds that migrate from Africa to Europe feed their nestlings mostly with moth caterpillars. The data presented show the mean dates of egg laying, hatching, and fledging of flycatcher young, and the 1980 and 2000 peak mass of caterpillars.

The most likely cause for the shift in caterpillar peak mass is

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#Question id: 11941

#Unit 7. System Physiology – Animal

Under conditions of normal renal function, which of the following is true of the concentration of urea in tubular fluid at the end of the proximal tubule?

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#Question id: 11942

#Unit 7. System Physiology – Animal

A patient’s urine is collected for 2 hr, and the total volume is 600 ml during this time. Her urine osmolarity is 150 mOsm/L, and her plasma osmolarity is 300 mOsm/L. What is her “free water clearance”?

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#Question id: 11944

#Unit 7. System Physiology – Animal

The maximum clearance rate possible for a substance that is totally cleared from the plasma is equal to which of the following?

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#Question id: 11945

#Unit 7. System Physiology – Animal

A patient has the following laboratory values: arterial pH = 7.13, plasma HCO3− = 15 mEq/L, plasma chloride concentration = 118 mEq/L, arterial Pco2 = 28 mm Hg, and plasma Na+ concentration = 141 mEq/L. What is the most likely cause of his acidosis?

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#Question id: 12070

#Unit 7. System Physiology – Animal

A 26-year-old man develops glomerulonephritis, and his GFR decreases by 50% and remains at that level. For which of the following substances would you expect to find the greatest increase in plasma concentration?

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#Question id: 12071

#Unit 7. System Physiology – Animal

The most serious hypokalemia would occur in which of the following conditions?