What type of relationship exist between two organisms when one organism benefits from the relationship and the other organisms become pray

2. which is the last step in the scientific method?

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?

Which muscle cell structure stores calcium ions that are used to trigger the contraction?