Answer:Carbon dioxide molecules
Explanation:
A. Trees regain their leaves
The answer Is B have a good day.
Answer:
Our body cells require oxygen to release energy.
Explanation:
The oxygen that we take in during respiration is used to break down the food we eat to release energy from it. When we breathe in oxygen, it diffuses into blood from the lung, where it is transported by red blood cells to the entire body to be used to produce energy.
Hcg secreted by placenta not the fastest method to detect pregnancy nor it is specific