Answer:
a. a portion of the population becomes isolated from the remainder of the population and experiences different selective pressures
Explanation:
This is an example of allopatric speciation Allopatric speciation is a form of speciation (formation of new species) that occurs as a result of geographic isolation. This means that a part of population becomes physically separated from the initial main population. There is no gene flow between these two populations and as a result the two populations reach a high level of genetic divergence. They can no longer interbreed which means they become two different species (speciation).
New populations evolve as result of mutation, genetic drift and natural selection.
For example, Galapagos finches are isolated from others by the ocean (geographic isolation). Because of the isolation, the finches don’t breed with one another. So, they developed unique characteristics and became endemic.
The answer to this would be a quartz.
Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO₄ silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO₂
so that is why quartz would be the best be carried in solution by a stream.
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Answer :Erwin Chargaff a Biochemist
Explanation:
He formulated the base paring of double helix of DNA. He reasoned that since the percentage of four DNA bases are of this proportions in human;
Adenine=30.9% and Thymine =29.4%;
Guanine=19.9% and Cytosine =19.8%
Then, the amount of adenine will always be equal to thymine,
And the amount of Guanine equals to cytosine based on this percentages of distribution.
(Adenine and Guanine are large, molecule of Purines, while thymine and Cytosine are Pyrimidine)
He concluded (although scientist believed, he did not explicitly stated this) that this should be the base paring patterns in DNA molecule. This is the first Chargaff Rule.
His second rule is that the DNA composition, in the relative amount of the four bases Adenine, Thymine, Cytosine and Guanine varies in proportion from one organisms to another. And this is the basis of molecular diversity.
Answer:
C
Explanation:
The more massive/heavier an object is, more inertia is involved.
The two richest ecosystems lie in tropical rainforests and coral reefs. On land, tropical rainforests contain many species variation with an abundance of species in bird, mammals, amphibians, and plants. While tropical rainforests occupy only 7 percent of the Earth’s land area, they contain over half of the world’s species. This may be because species richness tends to increase with decreased elevation, increasing solar exposure, and increased precipitation; that is, hot, rainy low-land areas have the most species. In contrast, deserts have low species variation because of low precipitation. On earth, water is majorly important the equation for life. Many of the species are genetically isolated because of habitat size and variation in the build of the land (mountains, equator location, etc) such as seen in the Galapagos islands and the Amazon rainforest, both near and in South America.
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