What must happen for most areas on Earth to experience all four seasons?

To experience all four seasons for most areas on Earth, the angle between the sunlght coming from the sun and how that sunlight hits the surface of the earth, must be different.

Explanation:

The angle towards the sun must be different. What I mean is the angle between the sunlght coming from the sun, and how that sunlight hits the surface of the earth, must be different.

In the summer that angle is the biggest ( on the equatotor is is exactly 90 degrees). In winter that angle is much less then 90 degrees In winter you hsve the steapest angle of all four seasons.

So, to experience all four seasons, the angle between the sunlght coming from the sun and how that sunlight hits the surface of the earth, must be different.

EXTRA:

When the sun Rays, hit the surface of Earth in the summer, the incoming solar radiation is really 'dence' in comparison to the winter. That is due to that angle between the sunlght coming from the sun, and how that sunlight hits the surface of the earth.

The bigger surface area is a result of strap angle

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .