Put the events in order to show how the global conveyor belt works. assume that you are starting with cold water on
the bottom of the ocean near antarctica, and it is gradually starting to warm as it moves north.
water cools and sinks to
water warms and rises to
water flows near surface.
water flows south to
water reaches norwegian
the bottom
sea
antarctica
surface.

the independent variable, or the one that is intentionally manipulated is the speed.

i don't know that i agree with that but what's the question ?

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.