Step 1: Defining "juxtapose."
"Juxtapose" signifies placing items in proximity, typically for comparison or contrast. A suitable synonym should convey the concept of being next to or united.
Step 2: Evaluating choices.
- Collective: Denotes a group, but not necessarily side-by-side placement.
- Adjacent: Implies being next to or bordering something, closely matching "juxtapose."
- Aligned: Means arranged in a straight line, distinct from side-by-side juxtaposition.
- Distant: Represents separation, the antithesis of juxtaposition.
Step 3: Determination. "Adjacent" is the closest synonym to "juxtapose," as both describe items positioned next to one another.Therefore, the correct choice is 2. Adjacent.
Final Answer: \[\boxed{\text{The correct answer is 2. Adjacent.}}\]