Answer:
It can be easily exploited by criminals, and it puts our undercover police officers and FBI officers in danger. Also, police officers are already swamped with work and criminal activity as is. It would also be ridiculously hard to get everybody already registered as a resident it the U.S. Take into account the different family types, and how hard it is for single mothers with children.
On the other hand, adding this, despite the obvious hardships, will make catching criminals much easier. Our blood DNA is unique to every human being. It would be extremely helpful to have a system like this in place. This would, at first, be hard to establish, but once it settles in, police officers would be able to spend much more time at home with their families instead of filling out paperwork for overtime.
Explanation:
A. Natural Selection. This is because the weeds that are not resistant to it die out before they can reproduce, but the resistant ones grow to maturity and then reproduce, passing down the resistance gene. Over time, the resistance gene would become a normal thing in weeds, while the non-resistant gene would not exist anyone, since the gene could not be passed on.
When a glacier melts, the ocean level rises therefore causing flooding and creating alien environments for those species that either live near the glaciers or on them.
Constructive Force I'm pretty sure.
