I believe that in some cases (eyes for cave-dwelling animals? antibiotic resistance in bacteria?) a trait can be turned off rather than lost completely. This means it would be easier to get it back than to evolve it from scratch.
I believe that in some cases (eyes for cave-dwelling animals? antibiotic resistance in bacteria?) a trait can be turned off rather than lost completely. This means it would be easier to get it back than to evolve it from scratch.