The thick, green stems and spike-like leaves of cacti and other drought-resistant bushes are adaptations to
A) increase gas exchange in oxygen-poor environments.
B) conserve water in dry environments.
C) speed up heating and cooling in environments that have little temperature fluctuation.
D) take up atmospheric nitrogen in nutrient-poor environments.
E) collect light in environments that have limited amounts of light.
B
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The evolution of jointed appendages has made __________ very successful.
Fill in the blank(s) with the appropriate word(s).
While shopping at your local drugstore, you stop at the blood pressure machine. It measures your blood pressure as 115/75 (good-that's healthy!). This number means that
A. arterial pressure is 115 mm Hg when the atria contract and 75 mm Hg in between atrial contractions. B. your sinoatrial node generates a 115 mV signal and your atrioventricular node generates a 75 mV signal. C. arterial pressure is 115 mm Hg when the ventricles contract and 75 mm Hg in between ventricular contractions. D. your sinoatrial node generates a 75 mV signal and your atrioventricular node amplifies this to a 75 mV signal. E. arterial pressure is 75 mm Hg when the ventricles contract and 115 mm Hg in between ventricular contractions.
Which of the following muscles contract during forceful exhalation?
a. the diaphragm b. external intercostals c. internal intercostals d. the diaphragm and external intercostals e. the diaphragm and internal intercostals
The ________ law of thermodynamics states that energy can be neither created nor destroyed.
A. third B. second C. first D. fourth