Concept:Ecological succession is the gradual change in species composition of a community over time, starting from a bare or disturbed area.
Explanation:Succession begins where life did not previously exist, such as a newly formed habitat like cooled lava, bare rock, or a new pond.
This is called primary succession.
It starts with pioneer species that colonise the lifeless area and gradually create conditions for other organisms.
Abundant food, space, light, or fertile land only support existing communities; they do not start the process of succession.
Therefore, the trigger is the availability of a newly formed habitat.
Answer:A. newly formed habitat