If the plane of the earth's equator were not inclined to the plane of the earth's orbit

If the plane of the earth's equator were not inclined to the plane of the earth's orbit there would be no change of seasons. When tilted, the hemisphere closer to the sun would experience summer, while the hemisphere that is relatively farther away would experience winter. If the earth were not tilted, the whole planet would be relatively equidistant from the sun, and hence, no seasons.