How will preventing the inactivation of sodium channels affect the signaling capability of a neuron?

The neuron becomes more positive. This can lead to the neuron reaching threshold and then initiate an action potential. When the sodium channels are NOT functional, the sodium can not enter and depolarize it. Therefore the threshold can not be met and action potential will not occur. If the sodium channels are inactive in a nociceptive neuron (carries information about pain), then it will prevent you from feeling pain.

Large asteroid and comet impacts. because they can have a huge impact on the environment, such as a loss of land, and crust on the earth with the big holes they produce. on the other hand, volcanic eruptions can also cause change within the environment by producing land, but im actually not quite sure which one would be a better answer, hopefully you read this and didnt just flat out choose the first sentence i have spoken! your welcome~