Question

circle the words or phrases that correctly complete the sentences.

1. thuy was learning about mid-ocean ridges and how they spread, creating more land. she wondered why earth doesnt keep growing bigger and bigger because of the new land. she learned that the reason earth isnt expanding is because of the many (trenches / mid-ocean ridges / mantles / subduction areas) that occur at ocean (mantles / trenches / mid-ocean ridges / subduction areas).

5-8

Explanation:

For question 4:

To solve this, we recall plate tectonics concepts. Mid - ocean ridges create new crust (seafloor spreading). For Earth not to expand, the new crust must be destroyed elsewhere. Subduction areas (where one plate subducts under another) are where crust is destroyed, and these often occur at ocean trenches (where subduction happens, like in deep - ocean trenches).

• First blank: Subduction areas are where the newly formed crust is destroyed, so "subduction areas" is correct (trenches are features, mantles are layers, mid - ocean ridges create crust).
• Second blank: Subduction areas (where crust is destroyed) occur at ocean trenches (the deep - ocean features where subduction takes place; mantles are layers, mid - ocean ridges create crust, so "trenches" is correct as subduction areas are associated with trenches).

Answer:

First blank: subduction areas; Second blank: trenches