Solar energy a. is a recent invention b. has been used for a ...

[saraeharris]

Solar energy
 a. is a recent invention
  b. has been used for a long time
  c. has not yet been successfully developed
  d. is indirectly the source of most of the energy we use

Question 2

Stepping barefoot off a rug onto a hardwood floor makes your feet feel cold. Why?
 a. The hardwood floor is at a lower temperature than the rug.
  b. The hardwood floor is at a lower temperature than your feet.
  c. The hardwood floor conducts heat away from your feet better than the rug.
  d. all of the above

[millet]

Answer to Question 1

B, D

Answer to Question 2

B, C