Answer: Option D. -> Mercury
Answer: (d)The planet nearest to the sun is mercury. Mercury is the smallest and closest to the Sun of the eight planets in the Solar System, with an orbital period of about 88 Earth days.

Answer: Option C. -> Rotation of Earth on its axis
Answer: (c)

Answer: Option B. -> Saturn
Answer: (b)

Answer: Option D. -> Aristotle
Answer: (d)

Answer: Option C. -> 6400 km
Answer: (c)The mean radius of Earth is 6371 km or approximately a 6400 km

Answer: Option A. -> Venus
Answer: (a)

Answer: Option A. -> Only one great circle can be drawn on a sphere.
Answer: (a)

Answer: Option B. -> 28 km
Answer: (b)

Answer: Option D. -> Saturn
Answer: (d)
Saturn is surrounded by a ring. Saturn has a ring around it because it is believed to be very big and has lots of moons, meaning it has a strong pull of gravity.
Another major reason is that the asteroids fling into their orbit and the rings are not solid.

Answer: Option B. -> Three parts
Answer: (b)
An eclipse occurs when a star (such as Sun) aligns with two celestial bodies, such as a planet and a moon. The closer body casts a shadow that intersects the more distant body. This means that “things get dark.”
The region of the shadow is divided into an umbra, where the light from the star is completely blocked, and a penumbra, where only a portion of the light is blocked.
Beyond the end of the umbra is a region called the antumbra. For an observer inside the antumbra of a solar eclipse, for example, the moon appears smaller than the sun, resulting in an annular eclipse.