Question

1. The idea of sea-floor spreading actually preceded the theory of plate tectonics.
A. The hypothesis was soon substantiated by the discovery that periodic reversals of the earth’s magnetic field are recorded in the oceanic crust.
B. In its original version, it described the creation and destruction of ocean floor, but it did not specify rigid lithospheric plates.
C. An explanation of this process devised by F.J. Vine and D.H. Mathews of Princeton is now generally accepted.
D. The sea-floor spreading hypothesis was formulated chiefly by Harry H. Hess of Princeton University in the early 1960’s.
6. As magma rises under the mid-ocean, ferromagnetic minerals in the magma become magnetised in the direction of the geomagnetic field.

• A. DCBA
• B. ABDC
• C. CBDA
• D. DBAC

Hint:

Scientific theories often unfold chronologically: origin → refinement → limitation → confirmation → example.

Answer 1

The Correct Option is A

Sentence 1 claims sea-floor spreading came before plate tectonics.
(D) introduces the origin — formulated by Harry Hess.
(C) gives the scientific explanation accepted today.
(B) adds a note on the early version’s limitations.
(A) describes how the theory was later confirmed using magnetic evidence.
Sentence 6 offers a specific example of magnetic mineral alignment in seafloor rocks.
Correct order:
1 — D — C — B — A — 6
DCBA