Answer:
commercialism
Explanation:
an association between two organisms in which one benefits and the other derives neither benefit nor harm.
Answer:
b. di uses across a synaptic cleft from a neuron to a muscle cell.
Explanation:
A neurotransmitter is di uses across a synaptic cleft from a neuron to a muscle cell. Neurotransmitters are chemicals which enable neurotransmission. In reaction to an impulse a motor neuron axon secretes a neurotransmitter and causes the muscle fiber to contract. It is a chemical messenger which passes on the signals across the chemical synapse.