I guess the stomach is held in place by a variety of Muscle cells, Epithelial cells, and connecting tissues; so the answer is: all of the above.
Predator and Prey relationships would have the most effect on an ecosystem's stability because they keep a limit number on the opposing population (ex. rabbit population can only get so high because wolves keep eating them / wolf population can only be so high because there is't enough rabbit to eat)
The correct answer is C, Oxygen.
During aerobic cellular respiration, oxygen combines with hydrogen ions and water is released as a by-product of respiration.
Explanation;
Cellular respiration allows organisms to release energy stored in chemical bonds of glucose, and other nutrients. The energy in glucose or other nutrients such as fats is used to produce ATP, which cells use to supply their energy needs. During aerobic respiration (in presence of oxygen), oxygen is reduced and water is produced together with carbon dioxide as by-products.
Severe weather conditions include hurricanes, tornadoes, blizzards, and droughts. Climate is the long-term average of the weather in a given place. While the weather can change in minutes or hours, a change in climate is something that develops over longer periods of decades to centuries.
