What color does cobalt-oxide produce? a. blue-violet b. red c. yellow d. green

The answer would be A. blue-violet

Explanation:

I'm just that smart . . . Jk, I took the test and looked at my notes.

photography had emerged as an elite art pursued by a few creative individuals for a few wealthy patrons. but now, said bauldelaire, it was succumbing to "the great industrial madness of our times." it was becoming a mass production industry that catered to middle-class tastes, including a taste for gadgetry. the stereoscope, the first 3d imaging system, had turned looking at photographs into parlor entertainment. a "thousand hungry eyes were bending over the peepholes of the stereoscope as though they were the attic-windows of the infinite.

pitch- the definition of pitch is as follows:

"the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone."