Indicate the main reason that sometimes it takes a day longer from new moon to full moon than from this full moon to the next new moon.

Ellipticity of the lunar orbit and the uneven movement of the moon along it. The maximum of this effect is when the Sun is on a line passing through the Moon and perpendicular to the semi-major axis of the lunar orbit.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.