The Earth's magnetic field is generated by:
a) salty water moving through the deep parts of the crust
b) convection currents in the atmosphere
c) movement of iron and electrical currents within Earth's outer core
d) aligned magnetic minerals within Earth's inner core
Ans: c) movement of iron and electrical currents within Earth's outer core
You might also like to view...
Fish don't live very long in water that has just been boiled and brought back to room temperature. Suggest why.
A. Since some of the water was evaporated while boiling, the salts in the water are now more concentrated. This has a negative effect on the fish. B. The nutrients in the water have been destroyed. C. There is now a higher concentration of dissolved CO2 in the water. D. The boiling process removes the air that was dissolved in the water. Upon cooling, the water is void of its usual air content, hence, the fish drown.
Which of the following regions in Sub-Saharan Africa seceded from its parent country, Ethiopia?
A) Shaba province B) Zululand C) Eritrea D) Biafra E) South Africa
Which of the following is usually lower in urban areas compared to rural areas?
A. temperature B. concentration of pollution C. visibility D. frequency of fog
Which of the following statements regarding nuclear energy is true?
A. Nearly all nuclear power plants worldwide are built far from water sources to prevent contamination. B. In a nuclear power plant, electricity is collected directly from electrons splitting off from fuel atoms. C. In a nuclear power plant, electricity is collected directly from the combination of electrons. D. The Pressurized Water Reactor and the Boiling Water Reactor are essentially the two main designs for a nuclear power plant. E. Decommissioning a nuclear power plant costs up to ten times as much as building it.