primary batteries primary beneficiaries primary beneficiary primary benefits primary benefit primary brain primary building block primary building primary business primary calendar primary camera primary campaign primary campus primary cancer primary caregiver primary care primary case primary categories primary causes primary cause primary cells primary cell primary challenge primary changes primary channel primary characteristics primary charge primary chemical primary choice primary circuit primary classes primary clients primary clinical primary coil primary colors primary color primary colours primary commitment primary competence primary components primary component primary computer primary concerns primary concern primary condition primary conduit primary connection primary consciousness primary consideration primary contact primary container primary containment primary content primary contribution primary contributor primary controller primary control primary coolant primary course of vaccination primary course primary crime scene primary criterion primary crushing primary culprit primary currency primary current primary customers primary data collected primary database primary data primary day primary dealers primary deficit primary definition primary demand primary design primary destination primary development primary device primary diagnosis primary difference primary directive primary disease primary display primary distinction primary distribution primary divisions primary documentation primary documents primary domain primary driver primary drive primary drug primary duty primary dysmenorrhea primary economic primary education to primary education primary effect primary efficacy analysis primary efficacy parameter primary efficacy primary elections primary election primary elements primary element primary email address primary emotions primary emphasis primary end-point primary endpoint of the study primary endpoint primary energy consumption primary energy demand primary energy needs primary energy source primary energy primary engine primary entry primary equipment primary evidence primary examination primary example primary exchange primary expenditure primary exports primary factors primary factor primary family primary feathers primary features primary feature primary fermentation primary field primary file primary filter primary flight primary focus primary food primary forests primary forest primary format primary forms primary formulation primary formula primary form primary forum primary foundation primary fuel primary functions primary function primary generalised primary goals primary goal primary group primary hard drive primary headaches primary health care primary healthcare primary home primary host primary hub primary hyperaldosteronism primary hypercholesterolaemia primary hyperhidrosis primary hyperparathyroidism primary hypertension primary image primary immunisation primary immunization primary immunodeficiency primary importance primary imports primary income primary indication primary indicators primary indicator primary industries primary infection primary infertility primary information primary ingredients primary ingredient primary input primary insomnia primary instrument primary insurance primary intention primary intent primary interest primary interface primary investor primary issue primary job primary keys primary key primary language of instruction primary language primary law primary legislation