Question

1. while some fish can keep individual body parts, such as the brain, heart, and muscles, warm, the opah was found to maintain a temperature higher than that of the surrounding water throughout its entire body. moreover, the opah kept its body temperature nearly constant as it descended to the colder depths. this was a novel _____ whole - body endothermy in a species of fish.

a) observation;
b) observation
c) observation,
d) observation:

Explanation:

To solve this, we analyze punctuation and sentence structure. The sentence "This was a novel ____ whole - body endothermy in a species of fish" is a complete sentence structure where we need to choose the correct punctuation after "novel ____".

• Option A has a semicolon, but a semicolon is used to separate two independent clauses, and here we don't have another independent clause after, so A is wrong.
• Option C has a comma, but a comma would create a comma - splice - like error here as there's no appropriate context for a comma after "observation" to connect to the rest of the sentence.
• Option D has a colon, but a colon is used to introduce a list, explanation, or quotation, and here "whole - body endothermy..." is not a list or an explanation that requires a colon introduction.
• Option B has no punctuation (or just the word "observation" which fits as the sentence is stating that this was a novel observation of whole - body endothermy in a fish species, with the correct grammatical structure without unnecessary punctuation.

Answer:

B) observation