Think about the chain of dominoes as a system. What are the system's inputs and outputs? How is the process started by the tiny domino at the beginning of the chain able to result in the toppling of the giant domino at the end of the chain?

It is evolution, because we all have some of the same traits like eye color or shape or ears.

Neurotransmitters are messengers responsible for communication between neurons. they are released from synaptic vesicles and are received by receptors.  the communication is referred to as neurotransmission. the following statement is true about neurotransmitters: a. they're stored in synaptic vesicles in the axon.

Digestion because it removes waste