Answer:
Evolution.
Explanation:
It might have acquired the ability to cause disease due to evolution. Due to evolution, the harmless bacteria can turn into infectious pathogens that cause diseases. Evolution is the change in the characteristics of a species over several generations due to the process of natural selection. This evolution in the bacteria occurs due to changing of environmental conditions which changes the genetic makeup of that harmless bacteria and turn into infectious pathogen.
Answer:
<u>Two ureters.</u>
These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop.
