It refers to an electric nerve impulse that travels through a neuron when it is set off by a "trigger", changing the neuron’s charge from negative to positive.

Which statements are true for invasive species? 1. they always stabilize an ecosystem. 2. they’re always successful in adjusting to a new habitat. 3. they often compete with the native species for resources. 4. they have the ability to displace the native species. 5. they’re always pests.