The U. S. service economy: a. is easily distinguishable from manufacturing firms. b. accounts for a significant portion of the U. S.'s economic output. c. is shrinking. d. is mostly composed of landscaping, salon, and daycare service businesses.

b. accounts for a significant portion of the U. S.'s economic output

Explanation:

The U. S economy is an economy where the main economic activity is the provision of the services rather than the manufacturing of goods and based on the growth of the services. And it accounts for a large shares of the U. S economic output of trade and commerce.