Which of the following explains why seasonal conditions vary in parts of the world a Earth is rotating on its axis the Earth's axis is tilted as it revolves around the Sun sea Earth orbit keeps it in line with the Sun D Earth takes 365 days to revolve around the Sun

The key factor that explains why seasonal conditions vary in different parts of the world is **the Earth's axis is tilted as it revolves around the Sun.**

This axial tilt (approximately 23.5 degrees) causes different parts of the Earth to receive varying amounts of sunlight throughout the year as the Earth orbits the Sun, leading to the changes in seasons. The other options you listed (Earth's rotation, its orbital position, and the time it takes to complete a revolution) contribute to climatic conditions and day-night cycles but do not directly explain the variation in seasons as well as the axial tilt does.