Which of the following organisms is NOT commonly recognized as a model organism?

• A. Fructose flies
• B. Mus musculus
• C. Drosophila melanogaster
• D. Homo sapiens

Answer: (D)

The organism that is not commonly recognized as a model organism is Homo sapiens, or humans. Model organisms are species that are extensively studied to understand biological processes, often because they have certain features that make them particularly useful for research, such as short life cycles, ease of genetic manipulation, and well-mapped genomes.

Commonly used model organisms such as Mus musculus (the house mouse) and Drosophila melanogaster (the fruit fly) are chosen for their practical advantages in laboratory settings, allowing researchers to conduct experiments that may be challenging or unethical to perform in humans. While humans are studied extensively in biomedical research, they are not classified as a model organism due to ethical concerns, the complexity of human biology, and the challenges associated with controlled experimentation in human populations.

In contrast, the other organisms listed, such as fruit flies and mice, are widely accepted in the scientific community as model organisms due to their utility in genetic, developmental, and biological studies.