Sentence sequence on DNA sampling in crime/ecology

Read the following sentences carefully.

1. Any viewer of crime dramas might think, though, that there is a better way.
2. What would really speed things up would be a means of sampling an entire habitat at one go.
3. But, these, too must first be detected and collected—and they will identify only the animal that dropped them.
4. Ecologists have thought of this, and it certainly works for things like animal droppings.
5. Just as DNA traces on an unwashed glass or a carelessly discarded cigarette butt can place a suspect as having been in a particular place, so can DNA shed by a creature as it goes about its business.

Which of the following options BEST arranges the above sentences in a logical sequence?