Final answer:
The most suitable model organism for studying the function of a vertebrate gene by creating a mutant strain would be Danio rerio, or zebrafish, which is a vertebrate and shares many genetic features with other vertebrates.
Step-by-step explanation:
If you want to determine the function of a vertebrate gene by creating a mutant strain, the most suitable model organism for your study would be C. Danio rerio, commonly known as the zebrafish. Arabidopsis thaliana is a plant and not suitable for studying vertebrate genes. While Caenorhabditis elegans and Drosophila melanogaster are valuable model organisms for various genetic studies, they are invertebrates and may not be ideal for studying certain aspects of vertebrate biology. Danio rerio is a vertebrate and shares many genetic similarities with other vertebrates, making it an excellent choice for studying gene function in vertebrates.
Model organisms such as zebrafish, fruit flies (Drosophila melanogaster), and nematodes (Caenorhabditis elegans) are widely used in biological research because they are easy to maintain, have short generation times, and their genetic systems are well understood. Zebrafish, in particular, are being used for studying organogenesis, because they develop rapidly, are transparent during early development, and have physiology and genetic make-up similar to other vertebrates.