Which of the following scenarios can be classified as a positive feedback loop? 1.increase in blood pressure to reduce the heart rate
2.increase in red blood cell production due to low oxygen levels
3.sweating to cool down skin cells
4.increased platelet production to help blood clotting

D

Explanation:

In order to prevent blood loss, the body needs a mechanism that amplifies the action that leads to clotting in a short period of time. This cascade or enhancement of a process is a positive feedback mechanism.

one half

Explanation:

The Sun's light comes from one direction, and it always illuminates, or lights up, one half of the Moon – the side of the Moon that is facing the Sun. The other side of the Moon is dark.