I think it's made up of 2 or more of the <em>same type</em> of atom.
Answer:
<em><u>Individual organisms live together in an ecosystem and depend on one another. ... One category of interactions describes the different ways organisms obtain their food and energy. Some organisms can make their own food, and other organisms have to get their food by eating other organisms</u></em>
<span>the tidal mouth of a large river, where the tide meets the stream.</span>
