Why does nuclear fusion require high temperatures and high densities?

Question $42$ options:

High temperatures produce particle speeds fast enough to overcome the Coulomb force. High density ensures that there are enough particle collisions for reaction.

High density ensures that there are enough collisions for reaction. High temperature is required to completely ionize atoms to the state of free nuclei.

Nuclei have positive charge and naturally repel each other via the Coulomb force. This force can be overcome by the weak nuclear force, which increases with temperature and density.

Nuclei have positive charge and naturally repel each other via the Coulomb force, which decreases with temperature. High density ensures that there are enough particle collisions for reaction.

Question $43(4$ points$)$

$$

You step outside into the sunshine and feel the warmth of the Sun. Which of the three ways to transport energy$$conduction$,$ convection, or radiation$$applies to this scenario?

Question $43$ options:

The warmth of the Sun is transported to you by radiation in space and both conduction and convection in Earth's atmosphere.

The warmth of the Sun is transported to you by radiation in space and conduction in Earth's atmosphere.

The warmth of the Sun is transported to you by radiation in which the heat energy is transferred by electromagnetic waves.

The warmth of the Sun is transported to you by conduction and convection in the Sun's photosphere and Earth's atmosphere.