I need some help with my econ homework. Can someone tell me if I am right on these?

1. When graphing cross-sectional data, one should ________.
A. place the various years on the X-axis

B.always be drawn using a line chart

C. investigate variables in a single time period

D. concentrate on collecting data on a single variable

My Answer: D. concentrate on collecting data on a single variable
2. Which of the following will cause the production possibilities frontier to shift outward?

A. an increase in the size of the labor force

B.a decrease in the unemployment rate

C. a decrease in the size of the capital stock

D. an inefficiency that has been corrected

My answer: B.a decrease in the unemployment rate

3. Shortages ________.

A. occur when the price is above the equilibrium price

B. are identical to scarcity, but just shown through the use of the demand and supply model

C. are due to the fact that quantity demanded exceeds the quantity supplied at a given price

D. can be eliminated by providing some of the good to each consumer

My Answer: C. are due to the fact that quantity demanded exceeds the quantity supplied at a given price

4. Quantity demanded ________.

A. is the amount of a good a consumer is willing and able to purchase at a given price

B. is identical to the quantity supplied

C. is a downward sloping curve

D. is the amount equal to what producers are willing and able to produce at given prices

My answer: B. is identical to the quantity supplied

Thanks