The price elasticity of demand measures how much

a. quantity demanded responds to a change in price.
b. quantity demanded responds to a change in income.
c. price responds to a change in demand.
d. demand responds to a change in supply.

Nikolas works in a shoe store as a salesperson. a teenage boy comes in looking for comfortable sports shoes because he is going on a hike. he tells nikolas he wants shoes that have velcro straps. nikolas shows him a wide variety of velcro-strapped shoes, but the customer rejects them because they don't feel comfortable. he asks for sports shoes with laces instead. nikolas once again shows him a wide variety. the boy is once again not satisfied and asks to see the velcro-strapped shoes again. nikolas is irritated but doesn't show his annoyance. what customer service skill is nikolas showing? nikolas is a. meekness b. patience c. persistence

Someone knows the answer i need in the exam

(a) what was the opportunity cost of non-gm food for many buyers before 2008? (b) why did they prefer the alternative? (c) what was the opportunity cost in 2008? (d) why did it change?