The ozone layer is comprised of ozone, an atom which is constructed of 3 oxygen molecules.
Hope that helped =)
The Rhine River<span> begins at the Rheinwaldhorn Glacier in the Swiss Alps and flows north and east approximately 820 metres. This </span>river<span> is arguably the </span>most important<span>waterway in </span>Germany<span> and is linked by canals to other </span>major rivers<span> in Western Europe.</span>
D. this is because when someone shows you a model of a cell, it is a diagram (typically) showing you the composition of it so that you can get a better idea of what the cell is and what the cell does.
