Step response of feedback system
G(s) is unstable because the step-response doesn't have a steady-state value. It goes to infinity.
F(s) is stable since its step response has a steady-state value near 0.1. It's underdamped response.
Fh(s) is stable since its step response has a steady-state value near 0.2. It's underdamped response with more oscillations than F(s).
Fl(s) is unstable because it doesn't have a steady-state value. It has a very large oscillations that start after some time.