Boys start to get acne at the age of approximately 12 years, with a range of 9 to 15 years old. As most girls will attest, boys on average mature later than girls. Early on in the onset of teen acne, the main lesions are blackheads and whiteheads.
The angular size (angular diameter, apparent size) of an object as seen from a given point is the visual diameter of the object measured as an angle. The visual diameter is the diameter of the perspective projection of the object on a plane through its center that is perpendicular to the viewing direction.
Resolution is the ability to 'resolve' differences; that is, to draw a distinction between two things. 1  High resolution means being able to resolve small differences. In a digital system, resolution means the smallest increment or step that can be taken or seen. In an analog system, it means the smallest step or difference that can be reliably observed. Some examples of resolution in FTA systems: Contact angle. Resolution = 0.01 degree. Interfacial tension. Resolution = 0.01 mN/m. Pump control. Resolution = 1 step.