Although green buildings cost on average (how much?) more to design and build than conventional buildings, the average payback time for this additional cost is about 6 years in energy savings alone. Group of answer choices 2% 6% 7% 4%The most densely-populated US city, New York City, has more than 27,000 people per square mile, and the per capita carbon dioxide emissions are less than one-third the US average.

a. True
b. False