What are the ways businesses or industries contribute to the contamination of water?

 In urban areas, sources of diffuse water pollution include: pollutants from car parks and transport, such as oil and brake fluid, rubber and metal from tyres and brakes, exhaust emissions, and detergents and grease from vehicle cleaning. heavy metals and pollution washed from roofs.

Explanation:

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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