Given the information "On Venus a day is equal to 243 Earth days", let's analyze what this statement means and determine the correct option among the given choices.
To start, it’s important to understand what is meant by the length of a day on a planet. The length of a day on any planet is the time it takes for that planet to complete one full rotation on its axis.
Now, let's consider each option:
a) The length of a planet's day is directly related to its distance from the Sun.
- This statement implies that as the distance from the Sun increases, the length of the day also increases.
b) The length of a planet's day is inversely related to its distance from the Sun.
- This statement implies that as the distance from the Sun increases, the length of the day decreases.
c) Venus takes 243 Earth days to orbit the Sun once.
- This introduces confusion between a day and a year. The time taken by a planet to orbit the Sun is actually the length of its year, not the length of its day.
d) Venus takes 243 Earth days to rotate once on its axis.
- This statement defines exactly what is provided in the problem: the length of a day on Venus.
Based on this analysis, the given statement "On Venus a day is equal to 243 Earth days" matches option d, which states "Venus takes 243 Earth days to rotate once on its axis".
Therefore, the correct answer is:
d. Venus takes 243 Earth days to rotate once on its axis.
