Question

read the text.
the arctic and the antarctic are both wild and icy expanses at the earths poles. but in many respects, theyre polar opposites! the arctic region, surrounding the north pole, is primarily sea. the northern reaches of north america, asia, and europe enclose the icy arctic sea. the floating arctic ice generally grows to a thickness of six to nine feet. at the other pole, antarctica is a high, dry continent, covered with snowy ice and surrounded by ocean. ice forms on the edges of antarctica, then drifts away to sea. antarcticas sea ice usually measures about three to six feet thick. the regions animals are different as well. polar bears, for example, live in the arctic, while penguins live in and around antarctica.
which organizational structure does this text primarily use?
cause - effect
compare - contrast
problem - solution

Explanation:

The text describes the Arctic and Antarctic, highlighting differences in their geography (Arctic is primarily sea, Antarctica is a continent) and ice thickness, as well as different animals (polar bears in Arctic, penguins in Antarctica). This is a comparison - contrast structure as it shows how the two regions differ. The cause - effect structure would involve showing a cause and its effect, and problem - solution would involve presenting a problem and its solution, neither of which is done here.

Answer:

compare - contrast