Which of the following could be considered a reliable source of scientific information? a. a scientist's presentation of experimental results at a scientific conference. b. a sales representative's glowing description of the benefits of a new drug. c. an elected politicians claims concerning the validity of a scientific study. d. a newspaper reporter's article about the results of a secret experiment.

The correct answer is option A- A scientific presentation of experimental results at a scientific conference.

Reason: A scientific presentation contains all the information which is based on experimentation and research of years and years. All the information is a scientific presentation would be factual and contain authentic data.

On the other hand, the other entire options even if contain information would not be authentic and contain errors and words of mouth.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

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