Why do biologists measure the number of trophic levels in an ecosystem?

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 have the same functions as eukaryotic poly-a tails, because this process is highly conserved throughout different species. b. prokaryotic poly-a tails aren't important, because prokaryotes don't have nuclei. c. prokaryotic poly-a tails have other functions, because prokaryotes don't have nuclei. d. prokaryotic poly-a tails are composed of a different molecular structure compared with eukaryotic poly-a tails.

Aeukaryotic cell must be from a plant if the cell a) a nucleus b) a nuclear envelope c) cytoplasm d) a cell wall

Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which statement is true of these bird species? a. they have adapted to different niches due to competition b. they have a carnivorous relationship with the tree species. c. they have adapted to different niches due to predation d. they have a symbiotic relationship with the tree species.