The worldwide exchange of carbon dioxide and oxygen during photosynthesis and cellular respiration helps to keep these gases at what level in the atmosphere? a Higher than predicted levels b Stable levels c. Levels that are unpredictable d Unsafe levels

## Step 1<br />The question is asking about the role of photosynthesis and cellular respiration in maintaining the levels of carbon dioxide and oxygen in the atmosphere. <br /><br />## Step 2<br />Photosynthesis is a process carried out by plants and some other organisms, where they convert light energy, usually from the sun, into chemical energy. This process also involves the absorption of carbon dioxide from the atmosphere and the release of oxygen.<br /><br />## Step 3<br />On the other hand, cellular respiration is a process that takes place in the cells of all living organisms, including plants. This process uses oxygen to break down glucose, producing carbon dioxide as a byproduct.<br /><br />## Step 4<br />The balance between these two processes helps to maintain the levels of carbon dioxide and oxygen in the atmosphere. Photosynthesis absorbs carbon dioxide and releases oxygen, while cellular respiration does the opposite.<br /><br />## Step 5<br />Therefore, the worldwide exchange of carbon dioxide and oxygen during photosynthesis and cellular respiration helps to keep these gases at stable levels in the atmosphere.