... 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. ... moderately pure, and they cannot survive if their water is loaded with toxic chemicals or harmful micro-organisms. If severe, water pollution can kill large numbers of fish, birds, and other animals,...