In which of these instances is demand said to be perfectly inelastic?

How long must a student wait for feedback on how they did on the accuplacer? a. 1 day b. 1 week c. 1 month d. immediate feedback (no wait)

He did chinese culture change during the warring states period

The smokey mountains have over 2,100 miles of rushing mountain streams and rivers that flow through the park. in each mile lives a diverse community of native fish, amphibians, insects, and larvae, some of which are found only in the southern appalachians. park managers and scientific researchers test many factors such as fish populations, the watersheds and water tests to determine a) too many lizards are present b) the water quality of the stream c) rainwater is running into local streams d) if visitors to the park are overstaying their welcome