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:
A group of bacteria that accumulate in layers and secrete a protective extracellular material. (Option A)
Explanation:
Biofilm is defined as one or more types of microorganisms collectively grow in different places. Organisms that form the biofilm include protests, fungi, and bacteria.
Dental plaque is an example of a biofilm. It is a known buildup of slimy bacteria that forms on the teeth surface. Biofilm can grow on different surfaces such as animal tissues, plant tissues, minerals, metal, etc.
Sorry its a very long answer-
1.) Failure to maintain the rule of law
The government's repeated failures to bring levels of violent crime under control contributed to an environment which saw people resort to violence without fear of arrest or successful prosecution.
2.) Border control
3.) Corruption
4.) Employment
5.) Education
This has been government's biggest failure and carries much of the blame for the high unemployment levels. It is arguable whether current state education is in its totality any better than that under apartheid. Only 1% of black matriculants achieve a good HG maths pass.
The education system is a good example where policy failures in one area compounded those in another.
6.) Slowing economic growth
7.) Foreign policy
8.) Service delivery
9.) Race relations
