An observation is something you saw happen whereas an inference is something you think will happen. You can guess that the water will fall through a static filled comb, but you observed the water moved away from the comb instead. (I saw this happen and I thought it was so cool)
Carbohydrate digestion begins in the mouth<span>.</span>
The answer is C. plants pull in CO2 and release oxygen
Photosynthesis produces oxygen and water. Photosynthesis is the result of a cycle. Humans use oxygen for respiration, the product produced from human respiration is carbon dioxide. Then plants absorb carbon dioxide from the air and turn it into oxygen with photosynthesis, this goes on and on as a cycle.