The main reason that most farmers use stem cuttings rather than just planting a seed is that a tree's genetic variation will occur. The seeds of many fruit trees tend to vary differently from the parent, because seeds themselves are produced by sexual reproduction (i.e they receive genes from a male and female to form). As they are a cross from two sets of genes, many fruit trees are not “true to seed”. Their seeds will produce a generally different variety of tree from the parent. When using stem cuttings, it's almost like a cloning process.
Overconsumption – situation where resource use has outpaced the sustainable capacity of the ecosystem. ...
Overpopulation – too many people for the planet to sustain. ...
Acid rain.
Biodiversity loss.
Deforestation.
Desertification.
Global warming/climate change.
Habitat destruction.
source - wikipedia.org
Answer:
The correct answer would be - d. With the end of genetic isolation gene flow took place
Explanation:
It is given that people of Troublesome Creek Kentucky were isolated and have a rare recessive allele that results in a blue tone to their skin. However, later these isolated people connected with the people from outside, and due which allow them to intermate. Intermating among populations from isolated and people from outside leads to gene flow.
Methemoglobinemia was present in the isolated population as they had both recessive alleles in their genotype and other hand people from outside might have heterozygous or both dominant allele genotypes that make them free from this disorder.
Due to the intermating and gene flow, the number of heterozygous conditions rises and after many generations slowly methemoglobinemia could have disappeared due to the masked recessive allele.
Which Characteristic of life best describes the process of homostasis