Earth’s magnetic field results from movements in the
a. mantle.
b. outer core.
c. inner core.
d. crust.

The correct answer is option B  

According to the scientists the magnetic field on the earth is the result of the movement of nickel and iron within its liquid outer core. The flow of nickel and iron is caused due to the interaction between the earth's core and its mantle.

The earth's core and its mantle are neither even nor they are evenly distributed. So, electrical currents are generated by this flow and this results in the generation of the magnetic field.

european union policies. the eu's long-term objective is to achieve levels of air quality that do not result in unacceptable impacts on, and risks to, human health and the environment. eu policies aim to reduce exposure to air pollution by reducing emissions and setting limits and target values for air quality.

the main environmental problems in western europe were: energy production/acid rain, nuclear power/waste, air pollution/climate, heavy metals, pesticides, water pollution, solid waste, and unforeseen accidents. many environmental problems are common to most european countries.