Leaf tissue layers penetrated by aphid stylet

Steps:

• Leaf structure starts with upper epidermis as the outermost layer.
• Below epidermis lies palisade mesophyll for photosynthesis.
• Vascular bundles deeper in contain phloem, where aphids feed on sap.
• Aphid mouthparts pierce sequentially from surface to phloem.

Why B is correct:

• B matches leaf anatomy: upper epidermis protects the surface, palisade cells form the next layer, and phloem lies below in vascular tissue for sap extraction.

Why the others are wrong:

• A starts with palisade cells, skipping the protective upper epidermis.
• C includes xylem before phloem and repeats palisade, ignoring actual vascular bundle layout.
• D places xylem after epidermis but before palisade, reversing mesophyll and vascular positions.

Final answer: B