Why might an author adapt a classic story for modern times

The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. This enables better survival and reproduction compared with other members of the species, leading to evolution

i think the answer your looking for is

enforced

even though there may be variations in human emotions over time, the poem “ a contribution to statistics” by wislawa symborska suggests that the only unchangeable characteristic is mortality.

the author poses a distinction between the approximate and non-approximate numbers which correspond to our need for certainty in life and the difficulty of achieving it. our efforts to measure the exact often fail because the world is not always clearly structured .the poem seems to imply   that the only thing that is certain and has an exact number is death.