[Solved] The rotator cuff muscles all have insertions on the greater and lesser tubercles of the humerus. Focus Controls: Elements in software or optical devices designed to adjust the clarity and sharpness of an image or to direct attention to specific tasks. Clear View: A term denoting an unobstructed and clear line of sight or understanding. Proper Objective: An aim or goal that is suitable and appropriately targeted for a specific task or endeavor. Optical Microscopes: Instruments that use visible light and a system of lenses to magnify small objects, allowing for the observation of details not visible to the naked eye.