**Question 41**
During which process does water vapor exit plant stomata?
A. Evaporation
B. Condensation
C. Transpiration
D. Combustion

**Question 42**
Which plants are best adapted for very dry, hot environments such as deserts?
A. CAM plants
B. C2 plants
C. C3 plants
D. C4 plants

**Question 43**
How does ATP provide energy to a cell?
A. It loses a phosphate group, releasing energy in the process.
B. It releases protons, which are used in the mitochondrion to create energy.
C. It releases electrons, which are a source of energy.
D. It shuttles electrons across the mitochondrial membrane to create potential energy.

**Question 44**
Which human activity has directly contributed to global warming?
A. Building houses with metal roofs
B. Combustion of coal, oil, and natural gas
C. Introduction of invasive species
D. Planting ornamental trees

**Question 45**
How would Earth change if the greenhouse effect didn't exist at all?
A. Earth would become extremely hot and never cool down.
B. Most of Earth's heat energy would be radiated into space.
C. All incoming sunlight energy would be absorbed.
D. Temperatures would be unaffected, and organisms would thrive.

**Question 46**
Why might anthropogenic global warming be dangerous?
A. Additional greenhouse gases in the atmosphere will affect airplane flights.
B. Changes in temperatures will cause glacial ice to cover more surface area.
C. Other planets will be affected by Earth's global warming.
D. Living organisms may not be able to adapt to the rapid changes in climate.

**Question 47**
How might global warming affect precipitation?
A. Deserts will receive more rainfall.
B. Storms will increase in intensity.
C. Rainfall near oceans will decrease.
D. Months of snowfall in higher latitudes will increase.

**Question 48**
Why are eating disorders that severely restrict food intake very dangerous?
A. Menstruation can cease, which may cause sterility.
B. They can lead to high blood pressure.
C. The risk of stroke can increase.
D. They can cause Type 1 diabetes.

**Question 49**
What happens first after chlorophyll absorbs light energy?
A. Water splits into H and O_2.
B. Carbon dioxide is converted to sugar.
C. Electrons are released and move to a higher energy level.
D. Hydrogen ions combine with electrons to produce NADPH.

**Question 50**
If necessary, our muscles can rely on an anaerobic (fermentative) pathway to metabolize glucose, but this can only last a short period of time. Why can't our cells survive very long under such anaerobic conditions?
A. The ethyl alcohol that builds up in muscles as a result of fermentation is toxic.
B. Fermentation doesn't extract enough ATP from glucose to sustain our energy-craving cells.
C. Anaerobic conditions create a "carbon dioxide debt" that must be repaid before cells die.
D. Lactic acid causes the cell to die when it's exposed to even lower concentrations.

**Question 51**
Which molecules are made during glycolysis?
A. ATP and NADH
B. Water and NAD
C. Oxygen and water
D. ADP and NAD+