Plant cells are distinguished by their rigid cell wall

Steps:

• Identify unique features of plant cells: cell wall, chloroplasts, and large vacuoles.
• Compare to animal cells: lack cell walls and chloroplasts, but have cell membranes and cytoplasm.
• Focus on root cells: roots lack chloroplasts due to no photosynthesis, so cell wall remains the key differentiator.
• Eliminate shared features like cell membrane and cytoplasm found in both.

Why B is correct:

• Plant cells have a rigid cell wall made of cellulose for structural support, which animal cells lack entirely.

Why the others are wrong:

• A. Cell membrane: Present in both plant and animal cells for regulating substance passage.
• C. Chloroplast: Absent in root cells (no light exposure) and typical animal cells.
• D. Cytoplasm: Jelly-like substance filling both plant and animal cells.

Final answer: B