1. What will the following code output:
2. What does the following code do:
3. How can you extract all items from a NumPy array that are greater than 5?
4. What is the result of the following:
5. If `arr` is a 1-dimensional NumPy array, what will `arr[::2]` do?
6. Which of the following will raise an error?
7. How do you calculate the dot product of two arrays `a` and `b`?
8. How do you get the unique values from a NumPy array `arr`?
9. Which method can be used to find the indices of non-zero elements in a NumPy array?