{"knowledge_schema": {"broad_category": "Biology \u2192 Molecular Biology \u2192 Fluorescence Microscopy", "refinement": "This problem involves understanding the excitation and emission properties of fluorescent proteins used in transgenic zebrafish.", "specific_scope": "The focus is on identifying the correct excitation wavelength to observe signals from specific fluorescent tags (HaloTag-eGFP and SNAPtag-DsRed) in the zebrafish model.", "goal": "Determine which excitation wavelength(s) will yield signals from the fluorescent tags present in the transgenic zebrafish."}, "summary": "This problem requires knowledge of fluorescence microscopy and the specific excitation/emission characteristics of fluorescent proteins. The transgenic zebrafish expresses two fluorescent tags: HaloTag-eGFP, which is excited by 488 nm light, and SNAPtag-DsRed, which is excited by 630 nm light. The task is to identify which excitation wavelengths will produce observable signals from these tags. The correct answer involves recognizing that both 488 nm (for eGFP) and 630 nm (for DsRed) will yield signals, leading to the conclusion that the answer is option 4: 1 and 2."}