- Life Sciences
regions or bundles of vascular tissue consisting of xylem and phloem separated by cambium.
movement of the Earth's continents as the Earth's tectonic plates shift.
a disease caused by the human immunodeficiency virus (HIV).
(also called autotrophic organisms) organisms that produce their own organic food, mainly...
a tough substance made from a modified polysaccharide that contains nitrogen. It is the main...