__ 16. What is the source of most ocean pollution? a. activities on land b. climate changes c. aquatic animals d. none of the above

## Step 1<br />The question is asking about the primary source of ocean pollution. The options provided are activities on land, climate changes, aquatic animals, and none of the above.<br /><br />## Step 2<br />Ocean pollution is primarily caused by human activities on land. These activities include industrial waste, sewage, and agricultural runoff, which are all carried into the ocean by rivers and streams.<br /><br />## Step 3<br />While climate changes and aquatic animals can contribute to ocean pollution, they are not the primary sources. Climate changes can lead to increased temperatures and acidification, which can affect marine life, but they do not directly cause pollution. Aquatic animals can contribute to pollution through their waste, but this is not the primary source of ocean pollution.<br /><br />## Step 4<br />Therefore, the correct answer is 'a. activities on land'.