The arrows in the diagram show continuous, cyclic movements from one subsystem to another without an end. Reflect upon your previous answers and knowledge of Earth’s subsystems to determine whether the arrows in the diagram best represent matter, energy, or both. Explain your answer and provide at least one example that occurred during the Precambrian era.

*will mark brainliest to first correct answer* photosynthesis led to increasing levels during the later proterozoic eon? a. oxygen b. water c. carbon dioxide d. none of the above

Pepsin is an enzyme in the stomach that breaks polypeptides into amino acids. pepsin functions best at a ph of around 1.5. what would be the most likely result if the ph of the stomach were increased to 5

Which best describes the scientific method? a. a path of clearly defined steps that must be followed in a particular order b. a possible answer to a scientific question based on knowledge or research c. the recipe for how to conduct an experiment that must be followed precisely d. the process of hypothesis and testing through which scientific inquiry occurs