What is the purpose for using cardinal points? They are used for measuring humidity, as navigational tools on vessels, measuring distances between different places, giving directions of places or objects in relation to others.

Question 3:
Cardinal points (North, South, East, West) are fundamental directions used to orient oneself and describe the location of places or objects relative to one another.

• The correct option is D.

The final answer is $\boxed{\text{D}}$

Question 4:
An arrow on a map, often called a North arrow or compass rose, is used to indicate the direction of North, which helps in orienting the map correctly.

• The correct option is D.

The final answer is $\boxed{\text{D}}$