What Is the Single Unique Characteristic That Distinguishes Extant Birds

question 30

Multiple Choice

What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?

• A) endothermy
• B) feathers
• C) an amniotic egg
• D) flight
• E) a four-chambered heart

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Definitions:

Cross Elasticity

Cross elasticity of demand measures the responsiveness of the demand for a good to a change in the price of another good, identifying substitute or complementary relationships.

Quantity Demanded

The total amount of goods or services that consumers are willing and able to buy at a specific price level, at a given point in time.

Normal Good

A type of good for which demand increases as the income of consumers increases, and vice versa.

Supply Schedule

A table of numbers showing the amounts of a good or service producers are willing and able to make available for sale at each of a series of possible prices during a specified period of time.