This is late but for anyone else who needs it...It's D. Far left
The answer is b
Explanation:
Tips
- write cue cards on respiratory system
- get someone to test you on your notes (friend,Mum,sister,brother ect)
- copy down diagrams of the system
- get someone to test you on Digram
- play online interactive games to test your knowledge on the respiratory system
- go through your textbook write a checklist things you know things you need to improve on.
- watch YouTube clips on the respiratory system
The answer is Rubidium (Rb)