Derek, a neuropsychology graduate student, works in a behavioral eating research lab. derek suggests to the lead investigator that injecting people with leptin will them lose weight.
his idea is quickly shot down by a classmate, who states, "not so fast, derek; "

a. as leptin increases, glucose absorption decreases
b. high levels of leptin inhibit insulin synthesis
c. leptin is metabolized by fat cells quicker than it is produced
d. obese humans already have high levels of circulating leptin

D

Explanation:

Obese humans already have high levels of circulating leptin

Leptin is a hormone secreted from fat cells that helps to regulate body weight. But in obese people they have unusually high levels of leptin. This is because in some obese people, the brain does not respond to leptin, so they keep eating despite adequate (or excessive) fat stores, a concept known as ‘leptin resistance’. This causes the fat cells to produce even more leptin.

this statement is true.

forests are public goods, available for everybody. when usage of such a good becomes interesting for consumers and its usage increases, there can be a risk of overexploitation. it is a non rival good therefore, if one person consumes the good it does not reduce the availability for subsequent consumers.

these caracteristics require the establishment of measures in order to prevent the destruction of a commonly owned space, for example, to restrict the amount of people that have access to the same time.

south, because if you took a map you would see texas is directly in the middle of east and west, but it is also downwards towards mexico, therefore it is south