Answer:
C. The heartbeat of the developing human can be heard via stethoscope.
False, Animal cells do “not” have cell walls.
The Mohs scale minerals from softest to hardest:
1. Talc (softest)
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond (hardest)
If I am wrong please tell me
The answer to your question is D. reliability !
hope this helps :^)