The part of an arch that projects slightly from the wall and the point where the arch springs from is called the a. voussoir c. pendentive b. impost d. keystone select the best answer from the choices provided a b c d

D keystone

Explanation:

The Keystone slightly protrudes from the wall at the point where the arch springs from- a pendentive is a curved triangle of vaulting formed by the intersection of a dome with its supporting arches , a Voussoir is a wedge-shaped or tapered stone used to construct an arch, and an impost ( the second closest to the definition ) is that part of an arch from which the arc swings upward.

i'm not sure i completely understand your question, but i will do my best.

i think the answer you are looking for is sequence. (see below)

a repeated melodic fragment would be best defined as repetition, while repeated chords (different or the same) could be a chord progression. however, you then mentioned the chord and melodic fragment beginning on higher or lower pitches, in that case, the answer could be best defined as a sequence. the definition of a sequence is as follows: "the restatement of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice."

let me know if this !