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immune system – n. the cells and tissues in the body that fight against infection
therapy – n. the work of treating illness
landmark – adj. event seen as famous or important in the history of something
fundamentally – adv. relating to the most important or main part of something
humble – v. having or showing a modest or low estimate of one's own importance
prestigious – adj. respected and admired
opportunity – n. situation in which it is possible for a person to do something
gratifying – adj. giving pleasure or satisfaction
