Answer:
A new mutation
Explanation:
A mutation refers to the random changes in the DNA of organisms. A mutation changes the allele and genotype frequencies by the introduction of a new allele in the gene pool.
However, mutations are not the major factor responsible for changes in the gene pool of a population as mutations are rare. The rate of mutations is very slow and does not allow it to serve as a major factor to change the allele and genotype frequencies.
The variables are defined as the factors in an experiment, which are liable to change. The variable can be dependent or independent. The Independent variable is a variable, which is unaffected by the changes in the other variables.
In this case, the brand of the food Shara feeds to the rats is independent factor, but it is changes in the system, so, it is an independent variable.
The effect on the weight of the rat is dependent on the brand of food they are consuming. So, the weight of rats is dependent variable.
The part of the root that contains transport tubes is the root hair. The primary role of the root hair is to absorb water and nutrients from the soil. They are hair-like and tubular in structure and are sometimes rarely visible by the naked eye.
The answer is Natural selection Hope it Helps
It is to replace old, worn out cells.
One single cell divides to two, etc. etc.
