Researchers have identified about substances that are made in our body and brain that act as neurotransmitters.\

Answer;

- 100

Researchers have identified about 100 substances that are made in our body and brain that act as neurotransmitters.

Explanation;

-Neurotransmitters are the chemicals which allow the transmission of signals from one neuron to the next across synapses. They are also found at the axon endings of motor neurons, where they stimulate the muscle fibers.

-Neurotransmitters enable neurotransmission, which is the process by which signaling molecules (neurotransmitters) are released by the axon terminal of a neuron (the presynaptic neuron), and bind to and activate the receptors on the dendrites of another neuron.

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.