I think this would be the environment. That's my guess
A secondary source is anything written after the fact
Answer:
The thrust of the air propels the balloon in the opposite direction
Explanation:
Humans ferment lactic acid in muscles where oxygen becomes depleted, which is why sometimes if you finish a run and don't stretch soon you have have discomfort. <span />
If your body lacks enzymes that break down carbohydrates, it would be unable to get sugar molecules for energy production. If you lacked the enzyme to digest proteins, you may not absorb enough amino acids?