Which of the following statements is false?
a destructive interference occurs when the crest of one wave overlaps the trough of another and their individual effects are reduced or cancelled out.
b when the crest of one wave overlaps the crest of another, their individual effects add together, which is constructive interference.
c constructive interference occurs when the crest of one wave overlaps the trough of another and their individual effects are reduced or cancelled out.
d for sound waves, destructive interference results in lower volumes.

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods

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.

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.