The answer is RNA, ribonucleic acid. It is similar to DNA except instead of thymine, it has uracil paired with adenine.
Ok so the first thing you need to do is look at t closely
DNA replication occurs in the nucleus. (The nucleus has a specific environment that ensures DNA is not degraded)
Transcription of genes to result in RNA occurs in the nucleus. RNA processing (e.g. the addition of a poly-A tail to each 3' end of mRNA) occurs in the nucleus as well.
Translation occurs in the cytoplasm.
Hope this helps! :)
B. By mutating their DNA in response to environmental conditions to gain beneficial traits.