I assume that the question here refers to the process of evolution. The "helpful variations" are small mutations that allow the organism to have a small advantage over other - and this organism can then pass this variation to its children better than other organisms, meaning that with time, more organisms will have it. This will accumulate over time and the percentage of organisms with this mutation will increase.
1.A, 2.C, 3.A, 4.D, 5.D, 6.D
it has been 98 years since women have been allowed to vote since the amendment was ratified in 1920. Almost 100 years aka 1 century.
Thinking a would be Father knows best, Perry Mason, I love Lucy. Hope this helps out
