Q: Simulations of the 20th century by climate models that exclude the observed increase ____ greenhouse gases fail to simulate the increase in temperature over the second half of the 20th century.
(a)of
(b)in
(c)by
(d)to
Correct Answer: (b)
The correct answer is (d): to. Subject: English Language | Sub-topic: Grammar & Vocabulary Note: This answer was determined through AI-based research. Verify against the official answer key when available.