Hi
It is true that on the Galapagos islands Darwin observed tortoises with a dome and saddle shaped shells, you can see both in attached image.
Darwin observed that Galapagos Tortoises had the shells with different shapes depending on the Island they live, For example: The tortoises with saddle shaped shells were able to reach up to eat leaves of plants while the tortoises with dome shaped shells would not reach up and they would eat food from on ground sources. This made him think that the differences in tortoise shell is also a strong evidence that indicates that how tortoises have adapted themselves to better get their food as per the available resources and how they have evolved from same ancestral specie into two different species. This point also helped him in proposing the theory of evolution by natural selection.
Hope it helps!
Pollution can come from both natural sources and human activities depending on the type of pollutant.
<h3>What is pollution?</h3>
It is the release of substances into the environment to the extent that the well-being of plants, animals, and humans starts getting affected.
Substances that are released into the environment to the extent that they start affecting the organisms in the environment negatively are known as pollutants.
Pollutants can come from natural sources or as a result of human activities.
For example pollutants such as oxides of sulfur, methane, carbon dioxide, etc. can come from natural processes such as volcanic eruptions, activities of microbes, etc.
Pollutants such as oxides of carbon and sulfur can also be generated as a result of human activities such as the burning of coal, technological inventions, etc.
More on pollution can be found here: brainly.com/question/23857736
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point, shift deletion, UV rays, radiations, genetics mutations, gene editing
That is just some method that gene can change within the DNA
