Answer:
Option D, the "biological ladder"
Explanation:
The food chain is the network of organism in which all are dependent on each other for their food, energy source and survival.
The circle of life depicts the time frame starting from origin of a life form till its death and the intermediate stages.
The tree of life basically determines which organism has evolved from which other organisms.
The biological ladder represents the development of species from simple form to a much complex form.
Hence, option D is the right metaphor
