The BVD stands for Back Vertex Distance, this is a measurement that is included on any prescription where the sphere or cylinder powers are higher than + or - 5.00D and to a lesser extent some prescriptions where it is less than this power.
Winged Drone | Alate | Male Ant. Drones are the only male ants in a colony. They are born from un-fertilized eggs. Drones are not like typical ants. They donât do any work in their nests, and they look more like wasps than ants. They are reproductive winged ants and so are alates.
They are also referred to as sex cells. Female gametes are called ova or egg cells, and male gametes are called sperm.Gametes are haploid cells, and each cell carries only one copy of each chromosome. These reproductive cells are produced through a type of cell division called meiosis.hey are also referred to as sex cells. Female gametes are called ova or egg cells, and male gametes are called sperm.