The company Nike is coming out with a special kind of shoe. The shoe is said to make athletes jump higher and run faster because of the lightweight material and bright colors. Other companies claim that the shoes are as average as any others on the market. To test the shoe, one hundred athletes of equal ability and speed are given the new Nike shoes and tested for a week in several skill areas. The experiment above is that:
1. poor because there is no control group
2. will test the hypothesis effectively
3. faulty in that the sample size is too small
4. well designed and will produce results for a testable conclusion

The evolution of molecular biology has made possible to establish a new classification of all organisms according to their DNA, and it's called phylogenetic classification. This classification group living beings according to their kinship it is established according to anatomical, and especially genetic, based on the similarity of genes between species.

This made it possible to discover kinship ties between species of which there is no suspicion of any morphological link between them, something which the old classification (the traditional classification) was incapable of doing (and this proves the importance of the DNA and genes in organisms classification.