Final answer:
In the context of physics, the pair of planetesimals with larger masses will experience a greater gravitational attraction, as long as they are composed of the same material and at the same distance apart.
Step-by-step explanation:
The question seems to be asking about the gravitational attraction between two pairs of planetesimals, which falls under the subject of Physics. According to Newton's Law of Universal Gravitation, the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Since the question states that each planetesimal is made of the same material and separated by the same distance, the pair that experiences the greater gravitational attraction would be the pair with the larger masses. This is because greater mass leads to a greater product of masses, and therefore a stronger gravitational force, assuming the distance remains constant. For example, on a larger scale, this principle helps explain how accretion allowed protoplanets to attract more planetesimals and grow in size within the early solar system.