Succession involves a pioneer species.

a. primary
b. tertiary
c. secondary
d. quaternary

A. Primary

Hope this helps, I'm sorry if I got this wrong. Have a good rest of your day. :)

A. Primary

Explanation:

A pioneer species is the one which colonize in an area where no living species previously existed before. It makes the environment suitable for the survival of the other species.

A primary succession occurs in a region where no living species existed before. The environment is unsuitable for the growth of diversity of species.

A pioneer species like lichen will grow over the rocks, will secrete acids which will wither the rocks. This will help in soil formation. The soil will facilitate the growth of new plants. Hence, the pioneer species will initiate the primary succession.

d. making up measurements to record.

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.