Question

correct the text by inserting three commas. (note: in this skill, serial commas are not optional.) snails barnacles coral and sea urchins produce their rigid parts by combining calcium and carbonate ions.

Explanation:

To correct the text, we need to insert commas to separate the items in the list (Snails, barnacles, coral, and sea urchins) as serial commas are required. So we place commas after "Snails", "barnacles", and "coral".

Answer:

Snails, barnacles, coral, and sea urchins produce their rigid parts by combining calcium and carbonate ions.