Final answer:
After a forest fire, the organisms that will begin secondary succession are small scrubs and wildflowers.
Step-by-step explanation:
After a forest fire, the type of organisms that will begin secondary succession are small scrubs (a) and wildflowers (d).
During secondary succession, after a disturbance like a forest fire, pioneer species such as annual plants and grasses are the first to grow back. These pioneer species create favorable conditions for the establishment of intermediate species like small scrubs and wildflowers. These intermediate species eventually pave the way for the return of the original forest community.
Therefore, after a forest fire, small scrubs and wildflowers would be the organisms that initiate secondary succession.