After transcription begins, several steps must be completed before the fully processed mrna is ready to be used as a template for protein synthesis on the ribosomes.
which three statements correctly describe the processing that takes place before a mature mrna exits the nucleus?
a. noncoding sequences called introns are spliced out by molecular complexes called spliceosomes.
b. a cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mrna.
c. coding sequences called exons are spliced out by ribosomes.
d. a translation stop codon is added at the 3' end of the pre-mrna.
e. a poly-a tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mrna.

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

Dr. kaylan is an ecologist who studies bird behavior. she sets up an experiment to test which type of food crows are most likely to eat when given a choice between walnuts, corn, and sunflower seeds. to perform her experiment, dr. kaylan places three food bins in an area frequented by cows. each bin contains one of the three food types. then, she measures how much of each food type is eaten every day for a month and summarizes the results of her experiment in the pie chart below. based on her results, dr. kaylan concludes that crows choose to eat corn more frequently than other food sources because it has a higher nutritional value. what is a reasonable alternate conclusion that can be drawn from dr. kaylan's data

How does upwelling affect coastal fisheries? upwelling damages nutrient supplies at coastal fisheries as the warm, nutrient-rich surface water is replaced by nutrient-poor, cold water. upwelling damages nutrient supplies at coastal fisheries as the cold, nutrient-rich surface water is replaced by nutrient-poor, warm water. upwelling improves the nutrient supply at coastal fisheries as the warm, nutrient-rich surface water replaces the nutrient-poor, cold water. upwelling improves the nutrient supply at coastal fisheries as cold, nutrient-rich water replaces the warm, nutrient-poor surface water.