Correct option is C
Explanation-
Proximate explanation – how the behavior happens (immediate mechanism: hormones, physiology, etc.)
Ultimate explanation – why the behavior evolved (evolutionary benefit, reproductive advantage, etc.)
Option C - Social communication through odours and increased group survival
Proximate cause: "Social communication through odours" — describes the mechanism (how animals detect and respond using chemical cues).
Ultimate cause: "Increased group survival" — describes the evolutionary advantage (why the behavior is beneficial for survival and fitness).
This matches the requirement of the question: both proximate and ultimate explanations are present.
So, the correct answer is Option C
Incorrect options-
Option A - Elevated heart beat and higher levels of stress hormone
Proximate cause is present (stress response mechanisms).
No ultimate cause — does not explain the evolutionary benefit of this behavior.
Option B - Scent marking along boundaries and high aggression
Proximate behavior is there (scent marking and aggression) but lacks the ultimate evolutionary outcome (e.g., territory defense leads to better reproductive success).
Option D - Higher maternal fitness and increased offspring survival
It has an ultimate explanation (why it's beneficial) but lacks the proximate mechanism (how this fitness is achieved physiologically or behaviorally).
