Why do traits tend to become more common in a species over time?

it's the release of intestinal gas, which forms as a result of digesting food. when partially digested carbs reach the colon, bacteria convert part of that food into hydrogen and carbon dioxide gasses. you cant stop the stink, its a gas that comes naturally.

explanation:

the oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf, but operationally is often referred to as beginning where the water depths drop to below 100 meters (328 feet), seaward from the coast to the open ocean.

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