The correct answer is:
<span>B.) At terminal velocity there is no net force
In fact, when the parachutist reaches the terminal velocity, his velocity does not change any more. It means that the acceleration acting on the parachutist is zero, and for Newton's second law, this means the net force acting on him is zero:
</span>

<span>because the acceleration is zero: a=0.
This also means that the two relevant forces acting on the parachutist (gravity, downward, and air resistance, upward) are balanced to produce a net force equal to zero.</span>
Answer:
heat required in pan B is more than pan A
Explanation:
Heat required to raise the temperature of the substance is given by the formula

now we know that both pan contains same volume of water while the mass of pan is different
So here heat required to raise the temperature of water in Pan A is given as


Now similarly for other pan we have


So here by comparing the two equations we can say that heat required in pan B is more than pan A
The answer would be (A) Protons
Options a to c can be the reasons for scientific models.
But to primarily answer scientific questions,that would require an empirical and experimental approach and not use of models.
Though after getting the answers, models can be built to further explain the answers.
<span>d. answer scientific questions.</span>