Distinguish between a common bar magnet and an electromagnet
What will be an ideal response?
A common bar magnet is composed of iron atoms, which produce the magnetic field via the motion of their electrons. An electromagnet is a coil of wire, usually wrapped around a piece of iron, that gets its magnetism from the electric current in the coil.
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When local environmental conditions change, background extinction can cause loss of species
Indicate whether the statement is true or false
Clouds form by convection because: a. the rising air warms adiabatically, becomes saturated and condenses
b. topography forces the air upward. c. the rising air cools adiabatically, becomes saturated and condenses. d. None of these choices.
The population cycles of lemmings in the arctic
A. occur because of the severe winters. B. involve interactions between lemmings and their predators. C. occur because lemmings are K-strategists. D. occur because of density-independent limiting factors.
Which of the following statements about less-developed countries is true?
A. They are highly industrialized. B. They usually have enough food, water, and shelter. C. The United States, Canada, and Japan are developing countries. D. Their populations continue to grow at high rates. E. Their populations are projected to decrease.