Consider the following statements and choose the correct answer:
1. Most interactions between living organisms, or between organisms and the abiotic phases of the ecosystem, are mutual activities of organisms met by responses
2. A feed-back loop can be defined as the relationship in which a change in some original state of being "feeds back" onto that original state to alter the rate or direction of further change
3. In a positive feed-back relationship, the feed-back process maintains a dynamic homeostasis, or steady state
4. In a negative feed-back relationship, the feed-back process leads to a self-sustaining change

A. Only 1 and 2 are true

B. Only 3 and 4 are true

C. Only 2, 3 and 4 are true

D. 1, 2, 3 and 4 are true

Answer: Option A