Take a look at the item again:
Coated with dust, (A)
the blinds filtered shadowy light into Adrian's cluttered
apartment, (B)
where clothing and empty take-out boxes littered the
floor. (C)
As flies buzzed around rotting bananas on the kitchen counter.
You wanted to do this:
Coated with dust, the blinds filtered shadowy light into Adrian's cluttered
apartment. Where clothing and empty take-out
boxes littered the floor. As flies buzzed around rotting bananas on the
kitchen counter.
Adding a period after apartment makes a fragment. Where clothing and empty take-out boxes littered the floor is a subordinate clause and cannot stand alone as a sentence.
You might want to review the rules.
Go back to the sentence to try again.