In areas of permafrost, stands of black spruce are frequently observed in the landscape, while other tree species are noticeably absent. Often these stands are referred to as "drunken forests" because many of the black spruce often "lean over" (that is, they are displaced from their normal vertical alignment). What is the most likely explanation for the unusual growth of these forests in this marginal habitat?

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#Question id: 12218

#Unit 7. System Physiology – Animal

The control of gastric acid secretion in response to a meal involves several events that take place over a 4- or 5-hr period following the meal. These events include

(1) a decrease in the pH of the gastric contents,

(2) an increase in the rate of acid secretion,

(3) a decrease in the rate of acid secretion, and

(4) an increase in the pH of the gastric contents. Which of the following best describes

the correct temporal order of events over a 4- or 5-hr period following a meal?

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#Question id: 12277

#Unit 7. System Physiology – Animal

A 45-year-old man adds lots of high-fiber wheat and bran foods to his diet to reduce his cholesterol. He loses 30 lb on the new diet, but has undesirable side effects such as stomach cramps, flatulence, and diarrhea. His gastroenterologist diagnoses a syndrome called gluten-enteropathy or celiac sprue. Which of the following is decreased in this man?

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#Question id: 31404

#Unit 7. System Physiology – Animal

Which of the following substances must be digested before being absorbed by the small intestine? 

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#Question id: 11537

#Unit 7. System Physiology – Animal

Testosterone is an example of a chemical signal that affects the very cells that synthesize it, the neighboring cells in the testis, along with distant cells outside the gonads. Thus, testosterone is an example of ________.

 I) an autocrine signal

 II) a paracrine signal

 III) an endocrine signal

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#Question id: 11538

#Unit 7. System Physiology – Animal

Prostaglandins are local regulators whose chemical structure is derived from ________.

TLS Online TPP Program

#Question id: 11539

#Unit 7. System Physiology – Animal

Aspirin and ibuprofen both ________.