The most accurate sight on a firearm is often considered to be a high-quality, variable-power scope, particularly for long-range shooting. These scopes provide magnification, allowing for precise targeting at various distances, and typically feature reticles designed for accurate holdovers and windage adjustments. For close-range applications, red dot sights can also be highly accurate due to their rapid target acquisition capabilities. Ultimately, the best sight depends on the intended use and shooting conditions.
Non adjustable blade sight.
Telescope
Rear notch, front blade.
Iron sights are the most common an are sometimes interchangeable.
A backsight is the rear sight of a firearm.
Depends on the firearm.
Depends on the target. Generally, but not always, a telescopic sight.
Depends on the firearm, what you are shooting, and where you are. With a rifle, firing from a supported position, such as a benchrest is the most accurate. In the field, the prone position is most accurate. However, that does not work well if you are in waist deep grass, or duck hunting with a shotgun. With a handgun, a two handed shooting stance is most accurate, and using a support makes that better.
Sight
Generally, a telescopic one. Like a scope on a Sniper rifle
the process of lining up a firearm's rear and front sights
It is the image that a shooter sees when looking through the sights of a firearm at a target, and shows the alignment of rear sight, front sight and target.