I'm not sure if I will answer the question you asked, as I many have interpreted it incorrectly. In natural selection, there must be variance in the gene pool, the total frequency of alleles in a population. Now, one of the organisms may have a gene that somehow helps them survive from the selective force much better compared to the others. If this does happen, over time the gene pool will narrow down to become just the genes of that organism that survived better in the first place because the rest would be taken care of by the selective force. So, the alleles and trait come from the first organisms that had the advantage over the others of its species.
The experimental group is the group you change from the normal. the fertilizer group is experimental
I think that the statement is true
1) occluding junctions
2) anchoring junctions
3) communicating junctions
Occluding junctions do not totally seal the space between cells and the resulting permeability varies greatly. I would say anchoring junctions are most likely with one of the other 2 junctions being least permeable.
