Final answer:
Zebrafish embryos' transparency makes them particularly useful for studying early development, permitting observation of processes that in other model organisms might be hidden or require invasive methods.
Step-by-step explanation:
Zebrafish (Danio radio) are especially useful in the study of early development because their embryos are transparent. This characteristic allows for detailed observation of embryonic development without the need for dissection or other invasive methods. Additionally, the transparency of zebrafish embryos facilitates the study of genetic expression and organ development, which is less visible in pigmented or opaque embryos.
Zebrafish serve as a valuable model organism in developmental biology, comparable to other organisms such as the African clawed frog and the sea urchin. While organisms like Xenopus levies are appreciated for their large embryos, and the sea urchin stands out due to the beautiful transparency of its gametes and early embryos, zebrafish embryos offer the unique advantage of being able to observe developmental processes in a living embryo. This aspect has advanced our understanding of vertebrate development and has important implications for medical research involving human diseases.