If the Earth did not incline on its own axis, the correct answer is option 2: The seasons would not have changed.

The inclination of the Earth`s axis is what causes the change in seasons. As the Earth orbits around the Sun, different parts of the Earth receive different amounts of sunlight. When a particular hemisphere is tilted towards the Sun, it receives more direct sunlight and experiences summer. On the other hand, when a hemisphere is tilted away from the Sun, it receives less direct sunlight and experiences winter.

If the Earth`s axis was not inclined, the Sun would always shine directly on the equator and the equator would be the only region to receive the same amount of sunlight throughout the year. This means that there would be no variation in temperature or weather patterns, leading to a uniform climate.

Therefore, without the Earth`s inclination, there would be no distinct seasons and the climate worldwide would be relatively constant.