year 8 biology crossword

Horizontal Words

1. a poisonous gas produced by carbon burning burning without enough oxygen (15)
3. a process in which energy is prodcuced by substances so it can be used (11)
5. A blood vessel that carries blood towards the hear (4)
7. a thin walled blood vessel that carries (9)

Vertical Words

2. A blood vessel that carries blood away from the hear (6)
4. the substance that carries blood in red blood cells (11)
6. when heart muscle cells start to die (12)