Taconite is a low-grade iron ore that is found around lake superior. the iron-bearing rock is found interlaced with quartz, chert and other minerals. the iron is separated out of the taconite using magnets so that it can be processed to for use in the production of steel in nearby states. what statement does not represent a concern by the department of natural resources about the use of taconite as a source of iron. a) the process to separate iron from taconite requires transportation by large vehicles over public roads. b) the separation of taconite involves chemicals that may lead to air and water and pollution. c) the area where taconite is mined is characterized by wetlands and streams. d) taconite is a non-renewable resource.

Option (D)

Explanation:

Taconite is a silica-rich and low-grade ore of iron. This iron ore was initially considered to be a waste rock due to the abundance of higher-grade natural iron ore. But now, with the decreasing amount of natural iron ore, the use of taconite is increasing. They are extremely hard rock and the iron ore present in this rock is extracted by the use of magnetism. Due to the heavier weight, these rocks are needed to be transported from one place to another using very heavy vehicles.

These rocks are obtained by the smelting process in which carbon is used to heat the iron ore. This emission of carbon into the atmosphere can contribute to pollution.  

These rocks are usually found in the streams and wetland areas. They are abundantly present on earth and not a non-renewable resource.

Hence, the most appropriate answer is option (D).

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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