Sample Answer:
Positive and negative feedback mechanisms are means by which Earth’s systems interact. Positive feedback involves an increase in the first variable leading to an increase in subsequent variables that ultimately leads to a greater increase in the first variable. Negative feedback involves an increase in the first variable, leading to an increase in subsequent variables that ultimately leads to a decrease in the first variable. Positive feedback speeds up the process and leads to instability. Negative feedback reduces changes in the system and helps to stabilize it.