Which of the following statements is true about immigration and emigration
a) immigration is balanced by emigration
b) immigration includes the birth rate, emigration includes the death rate
c) immigration and emigration can occur as a result of a change in climate
d) immigration is influenced only by abiotic factors and emigration only by biotic factors
e) immigration is a steady increase in the population emigration is a stead decline

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.