Question

why do scientists think earths core contains iron?
a. iron does not conduct electricity.
b. iron is a heavy element and would sink into the planet.
c. the crust also contains a great deal of iron.
d. iron is lighter than silicon.

Explanation:

• Option A: Iron is a good conductor of electricity, so this option is incorrect.
• Option B: Iron is a heavy element. During the planet - forming process (accretion), heavy elements like iron would sink towards the center of the Earth due to gravity, which is a valid reason for scientists to think the core contains iron.
• Option C: The crust has relatively less iron compared to the core. The presence of iron in the crust does not explain why the core has a large amount of iron.
• Option D: Iron is denser (heavier) than silicon. The density difference is related to the layering of the Earth's interior, and the statement in this option is factually wrong.

Answer:

B. Iron is a heavy element and would sink into the planet.