3. EM waves travel with a constant velocity of 3 x 107 m/s in a vacuum

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.

it was spontaneous.

"ain't i a woman? " is the name given to a speech, delivered extemporaneously, by sojourner truth, (1797–1883), born into slavery in new york state.sojourner truth' delivered her famous speech "ain't i a woman? " (which did not have a title at that moment) was given without any previous preparation. her dissertation took place at the women's convention in akron, ohio, in 1851.