The Test. Tests for Epstein-Barr virus (EBV) antibodies are used to help diagnose infectious mononucleosis (mono) if a person is symptomatic but has a negative mono test.he Test. Tests for Epstein-Barr virus (EBV) antibodies are used to help diagnose infectious mononucleosis (mono) if a person is symptomatic but has a negative mono test.
leaf scar. (botany). A mark on a stem, formed by secretion of suberin and a gumlike substance, showing where a leaf has abscised. 1  Facebook. 2  Twitter.
A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot. Foliage is a mass noun that refers to leaves collectively. Typically a leaf is a thin, dorsiventrally flattened organ, borne above ground and specialized for photosynthesis.Most leaves have distinctive upper (adaxial) and lower (abaxial) surfaces that differ in colour, hairiness, the number of stomata (pores that intake and output gases) and other features.xternal leaf characteristics, such as shape, margin, hairs, the petiole, and the presence of stipules, are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics. Leaves have determinate growth.