microscopic view of human b-cells which play a large role in the immune response system. - 白血球 幅插畫檔、美工圖案、卡通及圖標
normal artery and cholesterol blocked artery. clogged arteries caused by cholesterol. normal veins and varicose veins. - 白血球 幅插畫檔、美工圖案、卡通及圖標阻塞, 血液流動