Q. What is thick vein present in the middle of the leaf called?
Answer: Midrib
Notes: A thick vein seen in the middle of the leaf is called the midrib. Pinnately veined leaves have one large central vein, called the midrib, which extends from the base of the blade to its tip. Other large veins branch off on each side of the midrib. The leaves of beech, birch, and elm trees have such a vein pattern.

This question is part of 40000+ General Studies MCQ Series Course on GKToday Android app. Question Number: 47 in 12. Morphology and Adaptations in Higher Plants in above course in App.