I believe it’s Magnetic minerals
Explanation:
Fracking is the introduction of substances into a formation in order to increase they pore pressure and to increase natural drive of hydrocarbons.
Fracking has several environmental issues associated with it;
- Fracking leads to air pollution in case of blowout of gas pressure in formations, particles and dusts can become blasted into the environment.
- Proppants in fluids channeled into formations can lead to ground water contamination.
- In areas where fracking is done, there might be an exposure to harmful chemicals.
- Destruction of the natural habitats of animals.
The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>
