Why do higher trophic levels in most ecosystems contain fewer organisms than lower trophic levels?

2. what process do mrna and trna work together to complete? (3 points)

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?

Amines amides and amino acids are categories of