DNA is considered the blueprint of life, yet in eukaryotic organisms, such as humans, DNA never leaves the nucleus. Which of the following is the best explanation for how DNA codes into physical traits and characteristics, even though it never enters the cytoplasm?

There are no options to this question, however, it can be answered. The answer is:

DNA is transcribed into MRNA, which is translated into proteins responsible for physical traits and characteristics.

Explanation:

DNA is the genetic material of living organisms. As stated in this question, DNA is considered the blueprint of life. However, this DNA is permanently located in the nucleus of eukaryotic cells. The information in this DNA is used to synthesize a mRNA molecule in a process called TRANSCRIPTION.

This mRNA molecule then transports the genetic information from the nucleus to the cytoplasm (specifically the ribosomes) where the process of TRANSLATION i.e. synthesis of protein from mRNA, occurs. The produced proteins are responsible for the physical traits and characteristics.

Hence, the DNA never leaves the nucleus but it transfers it's stored genetic information to mRNA and subsequently proteins.