Enzymes lower activation energy through various means, including positioning substrates together in the proper orientation, applying torque on the substrates, providing the proper charge or pH microenvironment, and adding or removing functional groups on the substrates.
I am not totally sure but I think it’s B
A dog and a tick would have a parasitic relationship. Seeing as how, if anything, the tick is harming the dog and the dog isn't getting anything in return, but the tick is getting both a food supply and a host, their relationship would be classified as parasitic.
