What is found in high concentrations in the bloodstream in a vertebrate?

One of the purposes of transcription is to produce a sequence of bases that

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

14. which of the following codons code for threonine? a. ucg b. ugu c. cga d. aca