... concentrated as animals feed on plants and are consumed in turn by other animals. When they reach high levels in the body, heavy metals can be immediately poisonous, or can result in long-term ... London / rain. 52. after / he / read / instructions / what / do. 53. motion pictures / broaden / awareness / lifestyles. 54. not / mistakes / again. 55. Gagarin / astronaut / travel / space. ... contamination of streams, lakes, underground water, bays, or oceans by substances, is harmful to living things. Water is necessary to life on earth. All organisms contain it; some live in it; some drink...