Polygenic genetic traits follow a inheritance pattern

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.

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?