Identifying cell type from ultrastructural features

Steps:

• Observe for plant-specific structures like chloroplasts or cell wall.
• Check for universal eukaryotic features: nucleus, mitochondria, cell membrane.
• Note absence of chloroplasts indicates non-photosynthetic cell.
• Conclude it's an animal cell based on lacking plant organelles.

Why B is correct:

• Animal cells are defined as eukaryotic cells lacking chloroplasts and cell walls, but all cells have a plasma membrane that encloses cytoplasm, as per cell theory.

Why the others are wrong:

• A: Chloroplasts are absent in animal cells; nucleus is in both types.
• C: Mitochondria provide energy in both animal and plant cells.
• D: Identical to A; chloroplasts confirm plant cells only.

Final answer: B