Hydrogen has the smaller, lighter, simpler nucleus.
Helium has the larger, heavier, more complex nucleus.
Hydrogen nuclei are fused to form helium nuclei.
When that happens, energy is released.
Answer:
d) The trampoline pushes back up on the gymnast.
Explanation:
According to Newton's third law of motion; for every action force, there is an equal and opposite reaction force. The action force and reaction force are reciprocal to one another i.e. they act oppositely to one another. The reaction force acts in an opposite direction to the action force and vice versa.
In this question, a gymnast pushed down on a trampoline during a routine. This is called the ACTION FORCE. In conformity to Newton's third law, the trampoline pushes back up on the gymnast. This opposite force is called the REACTION FORCE.
An example of a system with decreasing gravitational potential energy is a ball in free fall.
At its initial height h, the ball has a gravitational potential energy equal to

where m is the ball mass and g is the gravitational acceleration. As the ball falls toward the ground, its height h decreases, and so its gravitational potential energy decreases as well, according to the formula

where h' is the new height of the ball.
The answer that best describe tropical continental is hot and sunny