Stones or pebbles (double check first though)
A.<span> Air pollution............................</span>
the basic unit of life is the cell
Water is important because, it's a part of all bodily functions
Hazardous substances are dangerous substances while toxins are poisonous substances. Hazardous substances may cause harm to an individuals health; they include acute toxins such as cyanide; substances harmful after repeated or prolonged exposure such as mercury and silica, among others. Toxic substances can be poisonous or cause health effects.
