X-Axis
Horizontal axis on a graph.
X-Chromosome (biology)
One of the sex chromosomes.
Xenograft
Tissue or organs from an individual of one species transplanted into or grafted onto an organism of another species, genus, or family. A common example is the use of pig heart valves in humans.
Xenolith
A piece of country rock found engulfed in an intrusion.
Xerophyte
Plant that have adaptations to survive prolonged periods of soil drought.
Xerophytic Leaves
The leaves of plants that grow under arid conditions with low levels of soil and water. Usually characterized by water-conserving features such as thick cuticle and sunken stomatal pits.
Xylem
Conducting tissue in vascular plants through which water and mineral nutrients are transported.