Why do historians refer to reconstruction as an "unfinished revolution"?

the answer is states.

valentina tereshkova

soviet cosmonaut valentina tereshkova became the first woman to fly to space when she launched on the vostok 6 mission june 16, 1963. valentina tereshkova was the first woman to go into space. in 1963, she spent almost three days in space and orbited earth 48 times in her space capsule, vostok 6.jan 22, 2018

the answer is a. hope this

because their parents smoke while in labor