Gases in both Earth's atmosphere and oceans have changed over its history. Scientists noted oxygen spikes in both the oceans and the atmosphere that coincide with changes in species on Earth. They report that the first oxygen spike resulted in a change from the microscopic life forms of 635 million years ago to large algae around 551 million years ago. A second oxygen spike occurring around 550 and 542 million years ago, according to the fossil records, resulted in an increase in

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hi my name is ashlynn and im 15

these macromolecules could either be amino acids, proteins or nucleic acids. they are responsible for the chemical changes and reactions that affects largely the cell and its composition. take for instance the cytoplasm of the cell where these organelles are settled. these simple organelles are composed of macromolecules which ignites and catalyses different functions that enables cells, in macro-perspective in motion and metabolism. in intestines for example, metabolism happens and breaking down parts of a food to simpler compounds that are used and these nutrients delivered throughout the body and again broken down by into smaller components.