A trilobite. Trilobites became extinct about 250 million years ago while a ammonite became extinct around the same time as dinosaurs(65 million years ago). You wouldn't find a human skull or a dinosaur footprint
Natural selection<span> and selective breeding can both cause changes in animals and plants. The </span>difference between<span> the two is that </span>natural selection<span> happens naturally, but selective breeding only occurs when humans intervene. For this reason selective breeding is sometimes called </span>artificial selection<span>.</span>
Chloride and sodium, I believe. Chloride and Sodium are believed to be salty, and this concentration makes up 90% of all dissolved ions in the ocean.
