Allele frequency is determined by looking at the dominant and recessive allele of a genotype.
Using the given, we can come up with the following computation for the allele frequency:
allele A = 100/300 allele B = 50/300 allele O = 150/300
Hence, the frequency of allele A is 0.33 or 33%, allele B is .17 or 17% and allele O is 0.50 or 50%.
The answer is all of the above
Answer - Many Types Such as
Golgi Body
Mitochondria
Nucleus
Chloroplast
Endoplasmic Reticulum
Reasoning - These are specialize Organelle which function in each part of doing their duty require the layers to keep it separate in maintaining certain materials they receive within the cell.
I think the answer is "the older it is"
Reason: I might be wrong but is something (like a shell) gets buried in something (like sand), overtime many things (like dirt, soil, sand, etc.) will be on top of the original. This will make layers. So, the older rock is on the bottom since it has been there for the longest and it gets covered by other stuff (causing the layers).
Hope this helps! :) (If I'm wrong, sorry :( )