Earth’s system is observed by noting changes and interactions of the oceans, land, the atmosphere, and organisms. Some of these changes and interactions happen daily, while others take place over long periods of time.
Which of the following changes and interactions happen on a daily basis?
A . The ocean tides change.
B . Mountain peaks are formed.
C . The atmosphere gains more oxygen and loses nitrogen.
D . Organisms develop new observable characteristics.
E . Volcanoes erupt.
Answer: A