1:3:3:9 is the correct answer
If we guide ourselves with the Moh´s scale:
Material scratches apatite → material is harder than 5.
Material is scratched by corundum → material is softer than 9.
Conclusion:
The hardness of the unknown material stands between 5 and 9.
Note:
Both apatite and corundum are defining materials (reference materials in the Moh´s scale). So, you can also give an answer using defining materials:
"It can either be an orthoclase feldspar, a quartz or a topaz".
Hope it helped,
BiologiaMagister
<u><em>This answer is dedicated to JaySL</em></u>
Answer:
It allows flexibility (adjustment) and survival of a population in the face of changing environmental circumstances.
Explanation:
The Xylem transports water and minerals while the Phloem transport organic nutrients
A a lot cause the moon control the wave of the ocean