Beware the Third Wish - S1-E31
Continuity mistake: The Wicked Wisher throws giant exploding coins onto the field TJ is on, as TJ runs towards the WW. The giant coins remain on the field after they explode, yet when TJ reaches the top of the field, there is no sign of the coins, or their remains.
Honey, I Shrunk the Rangers: Part 1 - S1-E16
Continuity mistake: The sign outside the Youth Centre changes in this episode, yet is back to normal in the next episode.
Chase Into Space: Part 1 - S1-E44
Continuity mistake: The space shuttle at Nasada - first it is below ground (as shown by the little amounts of light), then it is in the open (we see the Rangers get inside the shuttle, and it is a sunny day), and then we see the shuttle be raised up from the underground.
Continuity mistake: When Carlos is passed the ball during the football game, he has 2 defenders either side of him. In the next shot, Carlos hasn't moved, yet he now has no-one around him.
Continuity mistake: Bulk, Skull, Ashley, and Cassie are playing tennis, and they leave their rackets and balls behind them, at the back of the tennis court. When the Piranatrons attack, the rackets and balls are gone.
Chase Into Space: Part 1 - S1-E44
Continuity mistake: The Rangers try to use the Rescue Megazord's Artillery Power to defeat Divatox's monster. After it fails, the monster blasts energy at the Rescue Megazord - at which point its shoulder-mounted Artillery cannons disappear. They reappear again in the next shot.
Continuity mistake: One at a time, the Rangers jump down a tunnel into the Phantom Ranger's service tunnels. After TJ has jumped down, watch Carlos - his position changes between frames, and the camera is on him the whole time. First he is facing the hole, next he has his back turned - yet we do not see the movement.
Answer: The Rangers are human. Blue Centurion is a robot/cyborg.