Ghrelin is made in the stomach. It stimulates hunger by entering the brain and acting on the neurons in the hypothalamus to increase the activity of the hunger-causing nerve cells and reducing the activity of hunger-inhibiting cells. As the stomach empties, the release of ghrelin increases. Our hunger is influenced not only by our physical state but also by our memory of when we last ate and our expectation of when we should eat again. And although we humans as a species prefer certain tastes (such as sweet and salty), we learn to satisfy those preferences with specific foods eaten in the context of our families and our culture. Some of our taste preferences, such as the avoidance of new foods or of foods that have made us ill, have survival value.
Ghrelin is made in the stomach. It stimulates hunger by entering the brain and acting on the neurons in the hypothalamus to increase the activity of the hunger-causing nerve cells and reducing the activity of hunger-inhibiting cells. As the stomach empties, the release of ghrelin increases. Leptin is a protein produced by fat cells that is a hormone acting mainly in the regulation of appetite and fat storage. When your blood sugar levels are too low, your cells become starved for energy. At first, you might notice minor symptoms, such as hunger and headaches. However, if you don’t get your blood sugar levels up in time, you may be at risk for serious complications. Introducing more glucose into your body will help solve the problem of low blood sugar. Our hunger is influenced not only by our physical state but also by our memory of when we last ate and our expectation of when we should eat again, this is what the hypothalamus does. According to set point theory, after a time, your body will fight reduced calorie intake by sending signals (hunger indications) and slowing down your metabolism to attempt to bring you back to your normal set point. Basal Metabolic Rate is the number of calories required to keep your body functioning at rest. BMR is also known as your body's metabolism; therefore, any increase to your metabolic weight, such as exercise, will increase your BMR. Everyone's basal metabolic rate is different. Although we humans as a species prefer certain tastes (such as sweet and salty), we learn to satisfy those preferences with specific foods eaten in the context of our families and our culture. Some of our taste preferences, such as the avoidance of new foods or of foods that have made us ill, have survival value.
I think the best answer is D. It is thought that advances such as agriculture, literacy, and urbanization have not been accompanied by additional increases in brain size because the physiological cost of a bigger brain exceeds its benefit. The brain requires a lot of nutrients to function. Having a bigger brain would cost a lot rather than benefiting from it.
