<span>There are two hormones that determine whether you fell hungry or full -- ghrelin and leptin. Ghrelin sounds like gremlin, and it's the hormone that makes your stomach churn and says, 'Hey, you gotta eat.' The second, leptin, sends message from fat that tells your brain you are full.</span>
The vegetation of the tundra is composed of shrubs, grasses, mosses, lichens. Tree vegetation is very rare because of low temperature and short growing season.
<span>Estrogen is involved in a feedback mechanism associated with the follicular phase of menstruation. </span>
Decent from a common ancestor; natural selection.
