Q. Which of the following best illustrates FEEDBACK in development?

1. As tissue (X) develops, it secretes something that induces tissue (Y) to develop
2. As tissue (X) develops, it secretes enzymes that inhibit the development of tissue (Y)
3. Tissue (X) secretes RNA which changes the development of tissue (Y)
4. As tissue (X) develops, it secretes something that slows down the growth of tissue (Y)