Question

what caused the disappearance of land bridges?
a. a mass extinction
b. movement of the continents
c. formation of the polar ice caps
d. the end of the ice age

Explanation:

To determine the cause of land bridges' disappearance, we analyze each option:

• Option A: Mass extinction affects species, not land bridge geography. Eliminate.
• Option B: Continental movement (plate tectonics) is slow and not the primary cause of land bridge disappearance. Eliminate.
• Option C: Formation of polar ice caps would lower sea levels, exposing land bridges (opposite of disappearance). Eliminate.
• Option D: At the end of the Ice Age, glaciers melted, causing sea levels to rise. This submerged land bridges (e.g., Beringia) that connected continents during lower sea levels. This matches the cause.

Answer:

D. The end of the Ice Age