Which of the following is essential for birds to maintain their high metabolic rate?

A) Skin that is used as a respiratory structure
B) Hollow bones, which decrease body mass
C) Embryonic development in a shelled amniotic egg
D) A four-chambered heart, which maximizes oxygen delivery
E) Extraordinary coordination by a well-developed nervous system


D

Biology & Microbiology

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Which of the following choices best describes the relationship that exists between moisture and air temperature? 

A. The moisture-holding capacity of air decreases when it is warm and increases when it is cool. B. The moisture-holding capacity of air remains the same (warm or cool) and is not related to its temperature. C. The moisture-holding capacity of air increases when it is warm and decreases when it is cool. D. The moisture-holding capacity of air decreases as the higher altitude winds of the polar regions descend onto the continents.

Biology & Microbiology

Which of the following is a characteristic of a cell’s plasma membrane?

a. Having hydrophilic surfaces b. Being a static structure c. Having three layers of phospholipids d. Having hydrophilic fatty acid tails

Biology & Microbiology

What is required for facilitated transport to function properly?

a. ATP b. glucose c. glycolipids d. transport protein

Biology & Microbiology

Which of these conditions is a cancer that causes uncontrolled division of white blood cells, such that the number of cells greatly increases?

A) iron-deficiency anemia B) mononucleosis C) leukemia D) sickle-cell anemia

Biology & Microbiology