Producers because they make their own food such as plants..
Water treatment is any process that improves the quality of water to make it more acceptable for a specific end- use. The end use may be drinking, industrial water supply, irrigation,river flow maintenance, water recreation or many other uses, including being safely returned to the enviroment
Karyotype helps to study the presence and location of genes on chromosome. This also helps to find the mutations such as duplication or deletions.
Answer:
The correct answer is b. must be present in a population before natural selection can act upon the population
Explanation:
Genetic variation can be caused by mutation, recombination between chromosomes during meiosis and by fusion of two genetically different gametes during sexual reproduction.
This genetic variation is necessary for the evolution of any population. Natural selection acts on every individual and it decreases the frequency of those alleles that are not suited for the environment and increase the frequency of those alleles which helps the individual to survive in the changing environment.
Therefore genetic variation must be present in the population before natural selection act on the.
