When you see a blank at a sentence boundary, first test whether the text on each side is an independent clause (a complete sentence). If both sides are complete, a semicolon is often correct; a comma alone is wrong, and a conjunction like and usually needs a comma before it to join two independent clauses.
Hints
- Hint 1
Check what comes after the blank
Decide whether the words after the blank (“the transfer is inefficient…”) could stand as a complete sentence on their own.
- Hint 2
Check what comes before the blank
Make sure the part before the blank (“ecologists trace energy through…”) is also a complete sentence (has a subject and a verb).
- Hint 3
Match the boundary rule
If both sides are complete sentences, look for punctuation that correctly joins two independent clauses without adding extra words.
Step-by-step
- Step 1
Identify the clauses
The sentence has two complete thoughts:
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Clause 1: “ecologists trace energy through food …”
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Clause 2: “the transfer is inefficient, so much energy is lost …”
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- Step 2
Choose punctuation that joins two independent clauses
Two independent clauses can be joined with a semicolon, or with a comma plus a coordinating conjunction (like and). A comma alone would create a comma splice.
- Step 3
Select the option that correctly joins them
The semicolon correctly connects the two independent clauses: webs;