I think the answer is Releasing a black powdery substance on their trunks or shifting their range toward the poles.
Parasites benefit their hosts is the true statement. Parasitism is a symbiotic relationship in which one organism (the parasite) benefits from another organism and this other organism is harmed by the parasite.
The others aren't true because:
- the organism that is harmed doesn'y adapt and evolve it still is vulnerable
- it is a fact that parasites change from hosts
- phoresy is an association between two species in which one transports the other. This does not include killing the host (is possible, but it is not a condition under which you can call something a phoresy).
If referring to photosynthesis, carbon dioxide is brought into the cholorplast of the plant cell, it is then fixed to RUBP, it will go through a series of Redox reactions and become G3P. RUBP is then recycled and is used to fix more carbon dioxide. You need two G3P molecules to become glucose.
