This tree was constructed by comparing sequences of homologs of a gene that plays a role in development; Drosophila was used as an outgroup. The branch lengths are proportional to the amount of genetic change in each lineage; varying branch lengths indicate that the gene has evolved at different rates in different lineages.1. Drosophila2. human3. zebrafish4. chicken5. frog6. mouse7. lancelet

3. Zebrafish

Explanation:

Molecular phylogeny is mainly based on the improvement of gene models for the reconstruction of genes. it also describes the gene trees and species trees. Each gene tree tells us about the history of species and information of those genes.

Here, a specific gene tree is mentioned which is similar to the Zebrafish. Out of five vertebrate lineages, the Zebrafish shows genetic evolution most rapidly. It also shows the longest branches.

c

explanation: