Reproductive isolating mechanisms are barriers which impeded mating (prezygotic) or prevent the hybrid from developing properly (postzygotic) but the overall effect is to cause speciation by making it difficult for two diverging species to share genes. So one kind of mechanical isolation could be the usage of contraceptives. As of temporal isolation, or behavioral isolation could be exemplified by people who suffer from diseases that cause separation (such as HIV or cancer). I hope that this is the answer that you were looking for and it has helped you.
As the flower takes water that it needs to survive, the dye in it has no more density so it goes up with the water dying everything in its path blue.
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Did alleles for drug resistance occur in bacterial populations that afflict humans, prior to the widespread use of antibiotics in medicine and agriculture? a. No—mutations for drug resistance occur in response to antibiotic use. ... Yes—alleles for resistance arise due to random mutation, so are always present.
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