Answer:
“It can’t be more than ten degrees” would be the correct sentence.
Using “than” would accurately complete the sentence.
Step-by-step explanation:
The term “Than” is used to compare things while the term “Then” is only used in describing time.
For an example, you would you “than” if you were saying “dogs are better than cats”.
To use “Then” a sentence would be written as follows; “She lived in Iowa then”.
Hope this helps! :)