Neurotransmitters are small diffusible molecules such as acetylcholine, serotonin etc, which communicate nerve impulses across most synapses i.e the junction between two neurons.
They are regarded as chemical messengers because they are chemical substances, and they do aid transmission of nerve impulses for the neuron
You are looking at tissue under a microscope. One cell shows half the amount of DNA of some of the other cells. This cell is most likely to be in the G1 phase where the cell has just divided. Hope this answers the question. Have a nice day.
