Bio refers to study of living things + technology (is pretty straightforward- i dont think i need to explain this)
This means Vincent modifies the DNA of bacteria to study the function of their genes is the correct answer :)
not really familiar with all this but I think 1. Relative dating is where they estimate or relatively guess around how old it is so you could just put something like "an estimate of the age" or something
this is not the place to ask that