The Earth's orbit around the Sun is not perfectly circular; it's slightly elliptical. While the distance between the Earth and the Sun varies throughout the year, this variation is relatively small compared to the effect of the axial tilt. The more significant factor is the tilt itself.

Because of the 23.5-degree tilt, the angle at which sunlight strikes the Earth's surface changes throughout the year. During summer in the Northern Hemisphere, the Northern Hemisphere is tilted towards the Sun. This means the sunlight strikes the Northern Hemisphere at a steeper angle, concentrating the solar energy and resulting in longer daylight hours. Conversely, during winter in the Northern Hemisphere, the sunlight strikes at a shallower angle, spreading the solar energy over a larger area and resulting in shorter daylight hours.

The opposite occurs in the Southern Hemisphere. When the Northern Hemisphere is experiencing summer, the Southern Hemisphere is experiencing winter, and vice versa. The variations in daylight hours directly influence the amount of solar radiation received, which in turn determines the temperature and thus the season.

The student's statement is incorrect. The Moon's phases are not caused by the Earth blocking sunlight. Instead, the phases are caused by the changing angles at which we view the sunlit portion of the Moon as it orbits the Earth.

The Moon itself does not produce its own light; it reflects sunlight. As the Moon orbits the Earth, different amounts of its sunlit surface become visible to us. The amount of the sunlit portion we see changes because the relative positions of the Earth, Moon, and Sun are constantly changing. When the Moon is between the Earth and the Sun, the sunlit side faces away from us (New Moon). As it moves in its orbit, we see more and more of the sunlit side, resulting in phases like Crescent, Quarter, Gibbous, and finally Full Moon. The phases are a result of geometry – the changing angles of illumination as viewed from Earth, not the Earth blocking sunlight.

The student's diagram should depict the Earth as a sphere with a tilted axis of rotation. The Sun should be shown as a large source of light. Arrows should clearly indicate the direction of Earth's rotation (east to west). The diagram should show the Earth rotating, with different parts of the Earth being illuminated by the Sun at different times.

The diagram demonstrates the Earth's rotation by showing how different locations on the Earth's surface are successively brought into view of the Sun as the Earth turns. The apparent daily motion of the Sun is a direct result of this rotation. As the Earth rotates, a specific location moves from night into day and then back into night. The illuminated portion of the Earth's surface is experiencing daylight, while the unilluminated portion is experiencing night. The tilt of the Earth's axis is crucial to understanding why the entire planet doesn't experience day and night simultaneously. The diagram should visually represent this, showing how the angle of sunlight changes as the Earth rotates.