X inactivationThe normal inactivation of one of the two X chromosomes in females.
X-BandA frequency band of microwave radiation in which radars operate.
X-linkedThe presence of a gene on the X-chromosome.
X-linked diseaseA genetic disease caused by a mutation on the X chromosome. In X-linked recessive conditions, a normal female "carrier" passes on the mutated X chromosome…
X-Ray BackgroundIn solar-terrestrial terms, a daily average background X-ray flux in the 1 to 8 angstrom range.
X-Ray BurstIn solar-terrestrial terms, a temporary enhancement of the X-ray emission of the sun.
X-ray crystallographyThe diffraction pattern of X-rays passing through a pure crystal of a substance.
X-Ray Flare ClassIn solar-terrestrial terms, rank of a flare based on its X-ray energy output. Flares are classified by the order of magnitude of the peak burst intensity…
X-RaysThe part of the electromagnetic spectrum whose radiation has much greater frequencies and smaller wavelengths than those of ultraviolet radiation.
xanthophyllA yellow oxygen-containing carotenoid, present in chloroplasts.
xeniaThe immediate effect of pollen on some characters of the endosperm.
xenobioticA chemical compound that is not produced by, and often cannot be degraded by, living organisms.
xenogeneicRefers to organ s, genetically engineered ("humanized") todecrease the chance of rejection, that have been grown in an animal of another species for…
XenograftThe cells of one species transplanted to another species.
XenotransplantationThe transplantation of tissue or organs from one species to another species, typically from pigs to humans. Zoonoses are an important issue.
XenotransplantionA transplant of tissue from an animal of one species to an animal of another species.
Xeric (habitat)Low in moisture. Dry environmental conditions. Habitats or sites characterized by their limited water availability.
XeriscapeLandscaping that does not require a lot of water.
xerophyteA plant very resistant to drought, typically adapted to extremely dry environments.