Answer: past
Explanation: answers show that combonations can develope things
Answer:
oxygen from reaching your tissues and organs.
Explanation:
Carbon Monoxide is very dangerous to us and many other animals. It is a flamable gas that is bad for our blood cells. When we breath it in and it gets put into out blood, it cannot be used as a substitution for air, and you will suffocate.
...I think.
Carbon dioxide and oxygen
