AP BIOLOGY

Detailed explanation-1: -Veins Carry Blood Back Toward the Heart First the blood enters microscopic vein branches called venules. The venules conduct the blood into the veins, which transport it back to the heart through the venae cavae. Vein walls are thinner and less elastic than artery walls.

Detailed explanation-2: -The vein xylem transports water from the petiole throughout the lamina mesophyll, and the phloem transports sugars out of the leaf to the rest of the plant.

Detailed explanation-3: -In this study, we defined “lateral veins” as secondary veins that originated from the midvein and ran toward the leaf margin. For leaves that had more than one primary vein, only the midveins were measured.