Question

multiple choice question
a human gene can be placed into the genome of a bacterium, such as e. coli, and the bacterium will make the encoded protein. how is that possible?
this is possible because bacterial ribosomes are similar to human ribosomes.
this is possible because of the universal genetic code.
this is possible because bacterial cells evolved before human cells.

Explanation:

The genetic code is universal, meaning that the same codons code for the same amino acids in almost all organisms. This allows a human gene (which contains the genetic code) placed in a bacterium like E. coli to be transcribed and translated by the bacterial machinery to produce the encoded protein. Bacterial ribosomes are different from human ribosomes (prokaryotic vs eukaryotic ribosomes). The fact that bacterial cells evolved before human cells has no direct relation to the ability of bacteria to make a human - encoded protein.

Answer:

This is possible because of the universal genetic code.