Answer:
The most unique feature of “The Ninth” was that Beethoven included chorus and vocal soloists in the final movement. He was the first major composer to do this in a symphony.
B) herman von helmholtz
The trichromatic color theory<span> began in the 18th century, when </span>Thomas Young<span> proposed that color vision was a result of three different </span>photoreceptor cells<span>. </span>Hermann von Helmholtz<span> later expanded on Young's ideas using color-matching experiments which showed that people with normal vision needed three wavelengths to create the normal range of colors. Physiological evidence for trichromatic theory was later given by </span>Gunnar Svaetichin<span> (1956).</span>
<span>The illusionistic space of a two dimensional composition is called in sometimes, Implied space, the "literal" surface on which painting or drawing is created and 3 dimensional space can be implied in 3 dimensional space. It consists of height, width, and depth; it is actual space in which our bodies also stand.</span>