It is regulated by peristaltic movements. Then the pyloric sphincter will act as a valve at the junction between the stomach and duodenum, controlling the flow of chyme into the small intestine.
Since the liver is the primary organ for metabolism, then in the setting of liver injury there will be reduced metabolism of compounds such as hormones. If these hormones are not metabolized and degraded in the liver, then these hormone levels will increase.
<em>A particular example is that the hormone estrogen is increased in the setting of liver damage, causing males with liver failure to have feminine characteristics.</em>
They observe it, run tests on many different things, and do expirments
This change best illustrates the 3rd answer choice, Loss of Habitat.
The plants aren't migrating, but are rather only surviving in areas where there is enough moisture to support life. The wildflowers are not adapting to grow in dryer conditions, and the species is not going extinct, as there are still some areas where the plants can get enough moisture.
Hope this helped!