To answer this question, we need to identify the word that does not belong with the others. Let's analyze each option:
A. branch - This word is related to the parts of a tree.
B. dirt - This word stands out from the others as it is not directly related to trees or plants.
C. leaf - This word is related to the parts of a tree.
D. root - This word is related to the parts of a tree.
Based on the analysis, option B (dirt) does not belong with the others as it does not directly relate to trees or plants. Therefore, the correct answer is B.