Answer and Explanation: This is true that theories do change or get replaced overtime. We all know that in any scientific investigation the scientist put forth the theories which are basically the ideas explaining something particular. We also know that the world is experiencing constant changes and those changes could be of Technology or of overall world order so, whenever a scientist gives us the theory, that theory is made according to the situations and environment of that particular time and in future with the passage of time and with the advancement of Technology and other variables, scientist do need to re-evaluate theories. They either make some positive changes keeping in view the changing circumstances of the current situation or discard the theory altogether depending on its nature. The name research itself indicate that scientists research the already searched idea and in that way the New theory which comes after the modification of old theory or altogether the new theory takes place of the old one.
HABITAT.........................................................................
The Lederberg experiment that used the technique of replica plating showed that mutations are random and are not a result of the needs of the organism.
<h3 /><h3>What is a random mutation?</h3>
Random mutations are just that, they are changes in the genome of an organism that arise randomly. These mutations are the backbone of evolution and natural selection in that when they arise, if the organism becomes more adapted to survival as a result of this mutation, it increases its odds of survival through natural selection.
Therefore, we can confirm that The Lederberg experiment that used the technique of replica plating showed that mutations are random and are not a result of the needs of the organism.
To learn more about mutations visit:
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B: the gravel on the bottom of the aquarium, because it is not a living thing like the algae, plants and fish.
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Answer:
a stem or a leaf
Explanation:
Cuttings can be made from any part of the plant. Most frequently, however, either a stem or leaf is used. A stem cutting includes a piece of stem plus any attached leaves or buds. Thus, the stem cutting only needs to form new roots to be a complete, independent plant.
