What early form of photography used sheets of silver-plated copper to create photographic images, and became a popular way of making family portraits?

The Enlightenment

a. started in 1650. b. was the entire 18th century. c. was limited to the first half of the 19th century. d. dates from the early 19th century.

During the vocal sections in this selection, the guitars play?

a. ?the same melody that is being sung. b. ?dissonant, clashing harmony or chords. c. ?consonant, stable harmony or chords. d. ?the main melody.