Question

prior to the 20th century, many scientists believed that the continents had fixed positions on the earths surface. this notion was ______ by the theory of continental drift, proposed in 1912 by alfred wegener, who claimed that the continents were once joined together and had gradually drifted apart over millions of years.

which choice completes the text with the most logical and precise word or phrase?

choose 1 answer:
(a) validated
(b) challenged
(c) explained
(d) developed

Explanation:

Analyze the contrast in the text

The text states that prior to the 20th century, scientists believed continents had "fixed positions." It then introduces Alfred Wegener's theory of "continental drift," which claimed continents "gradually drifted apart."

Determine the relationship between the ideas

The idea of "fixed positions" directly contradicts the idea of "continental drift." Therefore, the theory of continental drift opposed, disputed, or questioned the older belief.

Evaluate the given choices

• (A) validated: Incorrect. The new theory contradicts the old belief rather than supporting it.
• (B) challenged: Correct. The theory of continental drift disputed the notion of fixed positions.
• (C) explained: Incorrect. Continental drift does not explain why they would be fixed; it argues they are not fixed.
• (D) developed: Incorrect. The new theory did not build upon or expand the fixed-position belief; it sought to replace it.

Answer:

• (A) validated
• (B) challenged (Correct answer)
• (C) explained
• (D) developed