NEET BIOLOGY

GENETICS AND EVOLUTION

EVOLUTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A geologist discovers a fossil in different layers of rock. Which layer is the oldest?
A
the fossils in the upper rock layers
B
the fossils in the lower rock layers
C
Either A or B
D
None of the above
Explanation: 

Detailed explanation-1: -The oldest layers are on the bottom, and the youngest layers are on the top. Because sediments sometimes include once-living organisms, sedimentary rock often contains a lot of fossils. Fossils are once-living organisms that have been turned into rock, in which the shape or form of the organism can still be seen.

Detailed explanation-2: -The law of superposition states that rock strata (layers) farthest from the ground surface are the oldest (formed first) and rock strata (layers) closest to the ground surface are the youngest (formed most recently). A fossil is the remains or traces of plants and animals that lived long ago.

Detailed explanation-3: -The oldest rock formation is, depending on the latest research, either part of the Isua Greenstone Belt, Narryer Gneiss Terrane, Nuvvuagittuq Greenstone Belt, Napier Complex, or the Acasta Gneiss (on the Slave Craton).

Detailed explanation-4: -Over time, layers of rock and sediment are laid down one on top of the other. The oldest rock layers (and therefore the oldest fossils) are always on the bottom, and the youngest are on top. This is referred to as superposition (super = above).

Detailed explanation-5: -law of superposition, a major principle of stratigraphy stating that within a sequence of layers of sedimentary rock, the oldest layer is at the base and that the layers are progressively younger with ascending order in the sequence.

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