Without seeing the specific picture of the frog you're referring to, I can provide a general guideline for identifying systems in biological images.
- Excretory System: This would typically involve features like the kidneys or bladder.
- Nervous System: Look for the brain, spinal cord, or nerves.
- Digestive System: Features include the stomach, intestines, or mouth.
If you can describe the picture or provide details about which structures are visible, I could help identify which body system is most represented!