An example of a pioneer species is a- a sparrowb- a lichen c- an earthwormd- a spider

The right answer is Lichen.

In ecology, a pioneer species is one of the first forms of life that colonize or recolonize a given ecological area.

Lichens are composite organisms resulting from a symbiosis between at least one heterotrophic fungus called mycobionte, representing 90% of all, and microscopic cells with chlorophyll (green algae or cyanobacteria autotrophic for carbon) called "photobionts" .

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs