A shell is considered as biotic (living) because it is a hard, rigid covering of many animals such as snail, sepia, pila, turtles, sea urchins. A shell is protective outer layer of these soft bodied animals.
B. Thick Atmosphere
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D. homologous chromosomes pair up
Answer:
The only thing that can scratch Corundum is diamond.
Explanation:
We refer to the Mohs Hardness Scale for the hardness levels. We can see that Corundum is a level 9 which is the second highest so at a level 10 we see diamond, therefore diamond is the only thing that can scratch Corundum.
