Think it is c but I could be wrong have not taken bio in a while
Commensalism is the term you are looking for
A mushroom or a mold commonly reproduces asexually by the formation of spores. Spores are produced in the sporangium through mitosis involving only one parent. They are released from the parent and germinate into new a mushroom or a mold. The offspring are genetically identical to that parent because their formation do not involve meiosis and fertilization. Spores allow fungi to expand their distribution and colonize new environments.
I believe the correct answer from the choices listed above is the third option. It is oxygen that is a necessary reactant for cellular respiration to occur. Cellular respiration, in a sense, is breaking down sugar in the presence of oxygen. Hope this answers the question.
Answer: Pollution, climate change, habitat loss, or invasive species