Ships have been using ballast water since the 19th century for stability. In the past, ships would discharge water from the ballast en route and at ports of call. Both United States and Australian ports receive more than 79 million metric tons of ballast each year. Currently, military and commercial ships are asked to perform a mid-ocean ballast exchange before arriving at port. What ecological issues is the mid-ocean exchange trying to prevent

One function of the poly-a tail on eukaryotic mrna sequences is to the mrna be transported from the nucleus to the cytoplasm. prokaryotic mrna also has a poly-a tail. choose the best explanation of the prokaryotic poly-a tail. a. prokaryotic poly-a tails are composed of a different molecular structure compared with eukaryotic poly-a tails. b. prokaryotic poly-a tails have the same functions as eukaryotic poly-a tails, because this process is highly conserved throughout different species. c. prokaryotic poly-a tails aren't important, because prokaryotes don't have nuclei. d. prokaryotic poly-a tails have other functions,because prokaryotes don't have nuclei.