The part of the ATP cycle in which analogous on spending money is ATP is broken down by water to ADP, energy and P. ATP or adenosine triphosphate is defined as a nucleotide that performs many essential roles in the cells and it is also an energy source that is used in living things.
Description 2 describes a commensal symbiosis. The answer is D, commensalism.
It should have prokaryotic cells as prokaryotic is associated with bacteria.
The three phases of signal transduction is (1) reception, (2) transduction, and (3) response. Reception involves the binding of a ligand, may it be a hormone or a neurotransmitter; to a receptor, may it be a membrane receptor, cytosolic receptor, or a nuclear receptor. After binding of the ligand to the receptor, there will be signal transduction of events that will ultimately form a response. For instance, insulin actin on the insulin receptor will trigger a series of events that will increase the transcription of the gene translating for glucose transporters and ultimately, increase the number of glucose transporters embedded in the cell membrane leading to increased glucose uptake in tissues.