Answer:
Water's flow through the hydrologic cycle is driven by Earth's external energy source – the Sun. Running water also moves and deposits sediment that ultimately becomes part of the rock cycle, whose energy source also includes Earth's internal heat energy.
Explanation:
Nitrogen fixation would not occur and that would mean that there would be a lack of nitrogen and it wouldn't be able to sustain life. Since nitrogen is an essential element in every amino acid, that also means in every protein. It essential to life and without it life would mostly likely not exist.<span />
As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acid and enzymes that digest food. Ridges of muscle tissue called rugae line the stomach. The stomach muscles contract periodically, churning food to enhance digestion.Mar 4, 2016
Probably to not contaminate food or accidentally poison it.
