Answer:
A) A transgene integrated into a heterochromatic region of the genome.
Explanation:
This is most likely the reason why the transgene is not expressed in the fifth cell line. It is likely that the transgene was integrated into a heterochromatic region of the genome. Heterochromatin consists of genetically inactive satellite sequences, and many of these are repressed to various extents. Moreover, because this is a tightly packed form of DNA or condensed DNA, it is inaccesible to polymerases and thus not transcribed.
B. He found similar fossils on different continents that are separated by oceans.
Caleb’s immune system will have the experience of getting rid of this antigen and know exactly what to do to overcome it efficiently.
