AQA GCSE · Question 07.5.3 · Inheritance Variation and Evolution
The remains which do not decay are replaced by __________.
Answer options:
A.
acids
B.
bones
C.
hard parts
D.
minerals
E.
rocks
F.
sediments
G.
soft parts
How to approach this question
Over millions of years, what happens to the hard parts (like the exoskeleton) that are buried? Water flows through the sediment and through the remains. What does the water leave behind that gradually turns the remains into stone?
Full Answer
D.minerals✓ Correct
Over a very long period, water containing dissolved substances seeps into the pores of the hard parts (like the trilobite's exoskeleton). These dissolved substances crystallise and form minerals, which gradually replace the original organic material. This process is called mineralisation or permineralisation. The result is a rock-like copy of the original organism, a fossil.
Common mistakes
✗ Choosing "sediments". Sediments surround the fossil, they don't replace the bone material itself.
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