Task: Class Definition Understanding (ontology: Food_Agriculture/Crop_Ontology)

Which of the following definitions best describes 'Stem thickness'?

A. The ratio of the legume fruit contour area to the bounding box area.
B. The thickness of the stem measured at the midpoint between the second and third nodes on a mature stem.
C. The specific leaf area of a single compound leaf, or the average specific leaf area of a sample of compound leaves.
D. The length of leaflets measured from the proximal margin of the leaflet to the distal margin of the leaf.

Answer: The thickness of the stem measured at the midpoint between the second and third nodes on a mature stem.