CIRCULATORY SYSTEM,
https://www.bbc.co.uk/bitesize/guides/zw3bfcw/revision/1
RESPIRATORY SYSTEM
https://www.bbc.co.uk/bitesize/guides/zsk8cj6/revision/1
https://www.abpischools.org.uk/topics/heart-and-circulation/the-prevention-and-treatment-of-cardiovascular-diseases/