Question

which is evidence that supports the dynamo theory?
a. convection occurs in the mantle very slowly.
b. silicon is a conductive material.
c. earths core contains mostly iron and nickel.
d. iron does not conduct electricity.

Explanation:

The dynamo theory explains Earth's magnetic field. It requires a conducting fluid (like molten iron - nickel in the core) for the dynamo effect. Option C mentions Earth's core has mostly iron and nickel (conductive materials). Option A is about mantle convection (not related to dynamo theory). Silicon (Option B) is not the main component for Earth's dynamo. Iron conducts electricity (so Option D is wrong).

Answer:

C. Earth's core contains mostly iron and nickel.