instruction:
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
question:
Marginal utility is a concept from economics that describes the change in utility from consuming more or less of a good or service .
answer:
In economics , utility is the satisfaction or benefit derived by consuming a product ; thus the marginal utility of a goods or service is the change in the utility from an increase in the consumption of that good or service .


question:
The Hondo and the Sarstoon River make the northern and southern border .
answer:
The undulating courses of two rivers , the Hondo and the Sarstoon River , define much of the course of the country 's northern and southern boundaries .


question:
The coqui ́ is an important symbol of Puerto Rico .
answer:

The common coqui ́ is a very important aspect of Puerto Rican culture , and it has become an unofficial territorial symbol of Puerto Rico .


