Identify the type of signaling for each of the following: Acetylcholine being released by a presynaptic neuron and causing muscle contraction of the post-synaptic cell
Thyroid-stimulating hormone being released from the pituitary gland and traveling to the cells of the thyroid gland
T-cells responding to IL-2 that they have released during an immune response
Growth factors affecting cell development
Ions flowing through gap junctions to allow cardiac cells to contract simultaneously