Unlike birds, which are highly sensitive to atmospheric pressure, people have found that paragliding require the use of a variometer since detecting thermal currents are impossible using normal human motion sensitivity

1) that paragliding require the use of a variometer since detecting thermal currents are impossible using normal human motion sensitivity

2) the use of a variometer crucial for paragliding since it is impossible to detect thermal currents using normal human motion sensitivity

3) that paragliding requires the use of a variometer since detecting thermal currents are impossible using normal human motion sensitivity

4)paragliding to require the use of a variometer due to the fact that detecting thermal currents is not possible with the use of normal human motion sensitivity

5) that paragliding requires the use of a variometer since detected thermal currents are impossible to handle using normal human motion sensitivity

OA: 2