Between 1957 and 1961, thousands of expectant women in 30 different nations ingested a common antinausea drug of the time known as thalidomide. A study of found that if the thalidomide was ingested only after day 54, then no harm occurred to the fetus, but if ingested prior to day 54 the fetus could be born with malformed or absent limbs.

A study of those newborn babies

Explanation:  

Studying the infants from these pregnant women lead the researchers to find out that this drug interfered with the process of limb formation if the pregnant woman had taken this drug anytime during the 26 days critical for limb formation and development. In this way, it makes for an instance where nurture had disrupted nature.

not sure but try c two haploid cells

explanation:

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.