Relative to its surface, friction is constant (this is known as the friction constant). The speed is decreasing on an object because friction is acting on it over a period of time, not because friction is getting stronger.
Yes friction slows down motion and not force
yes
You can describes the friction
This entirely depends on what the graph is charting, but generally, an upward curve reflects an increase in some quantity like distance or acceleration and is a positive correlation with speed increase. However, it could be an increase of resistance or friction, which would decrease speed.
decreas
increased because the road is rough
If you mean Bernoulli's principle, it's the statement that an increase in the speed of a fluid produces a decrease in pressure and a decrease in the speed produces an increase in pressure.
Presence of friction, incline and so on.
Gravity, friction, or wind drag.
Decrease friction .
INCREASE
You can describes the friction
Either the friction or density of the snow.
Wax, due to it filling the pores that cause friction will reduce friction.
lubrication decreases friction unless you're lubricating with sandpaper.
To decrease the forces that opposes motion
This entirely depends on what the graph is charting, but generally, an upward curve reflects an increase in some quantity like distance or acceleration and is a positive correlation with speed increase. However, it could be an increase of resistance or friction, which would decrease speed.
decreas
increased because the road is rough