1. The graph below shows the solute concentration inside a paramecium over time. What is happening at the time indicated by the pointer?
A. Water is moving rapidly into the paramecium by osmosis.
B. Water is moving rapidly out of the paramecium as the contractile vacuole contracts.
C. The paramecium is having a meal.
D. Solutes from the surrounding water are diffusing through the cell membrane, causing the solute concentration inside the paramecium to rise.
2. Which of the labeled structures controls the water balance in the paramecium?
A. Structure A
B. Structure B
C. Structure C
D. Structure D
3. The graph below shows the paramecium solute concentration through time when the water solute concentration is 1.25%. Which of the following graphs show the paramecium solute concentration when the water solute concentration is 1.10%?
A. Graph A
B. Graph B
C. Graph C
D. Graph D
4. Which of the following statements correctly describes the response of paramecium to changes in water solute concentrations?
A. When water solute concentrations rise, the paramecium reduces its rate of contractions.
B. When water solute concentrations rise, the paramecium increases its rate of contractions.
C. When water solute concentrations fall, the paramecium reduces its rate of contractions.
D. The rate of contractions remains constant no matter what the water solute concentration is.
5. Which of the following is not an example of homeostasis?
A. After plunging into icy-cold water, Gary's core body temperature rapidly drops.
B. While exercising, Julia's heart rate and breathing increase to balance the increased oxygen use by her muscle cells.
C. On a hot day, Martin doesn't drink very much water. His kidneys respond by removing very little water from his blood, resulting in yellow, concentrated urine.
D. After eating a candy bar, April's pancreas secretes insulin, causing excess blood sugar to be removed.
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