Question

read the passage.
goodbye, cod
the atlantic cod was once the mainstay of the united states fishing industry. however, warming of the ocean along the shores of new england has caused the stock of cod to disappear almost completely. according to scientists at the gulf of maine research institute, the gulf of maine is heating up faster than a majority of the rest of the planet’s oceans. as a result of warmer ocean waters, female cod produce fewer offspring, and these fish are less likely to survive to maturity. even though recreational cod fishing was banned in 2014, and strict limitations were placed on the number of fish commercial fishermen could catch, these measures have not been enough to protect the cod.
what is the main, or central, idea of the passage?
female cod are producing fewer offspring in the gulf of maine.
because the gulf of maine is warming unusually quickly, atlantic cod are disappearing.
because cod used to be abundant in the atlantic, it was once the backbone of the u.s. fishing industry.

Explanation:

To find the main idea, we analyze each option:

• The first option focuses only on female cod producing fewer offspring, which is a detail supporting the main idea, not the main idea itself.
• The second option connects the unusual warming of the Gulf of Maine to the disappearance of Atlantic cod, which encompasses the key elements of the passage (ocean warming, cod population decline).
• The third option only talks about cod's past importance to the fishing industry, not the main issue of their current decline due to warming.

Answer:

B. Because the Gulf of Maine is warming unusually quickly, Atlantic cod are disappearing.