Step 1: Read the clue first.
Search the passage for the phrase "Both influence each other". The word just before it is the answer to the question.
Step 2: Test choice 1.
Choice 1 is dialectical. It is the word right before the explanation that both sides influence each other, so it fits.
Step 3: Test choice 2.
Paradoxical would mean the two ideas clash with each other, but the passage says they shape each other, so choice 2 fails.
Step 4: Test choice 3.
Relational only repeats the idea of a relationship and is not a term used in the passage, so choice 3 fails.
Step 5: Test choice 4.
Differential is not found in the passage in this sense, so choice 4 fails.
Final Answer:
The passage word is dialectical, so choice 1 is the answer. \[ \boxed{\text{Option 1}} \]