How can scientists determine wind speed

A: Wind is caused by an air pressure change.  You can measure the velocity of the wind using a device called an anemometer. An anemometer looks like a weather vane but instead of measuring the way the wind blows with points, it has four cups so it can measure wind speed more accurately.

-SТОЯМ

offline recommendation systems option b

because recommendation systems produce a list of two ways

1. through collaborative filtering

or

2. through content-based filtering