Inspite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival ?

The correct answer is Resource partitioning.

In nature, when two or more species compete for the exact same resources (such as food, nesting sites, or feeding times), it can lead to intense interspecific competition. According to Gause's Competitive Exclusion Principle, two species competing for the same limiting resources cannot coexist indefinitely if all other ecological factors remain constant; one will eventually outcompete and eliminate the other.
To avoid this competitive exclusion and ensure their survival, competing species often evolve mechanisms that promote coexistence. One of the primary mechanisms is resource partitioning.

Resource partitioning occurs when species divide resources to avoid direct competition. They can achieve this by:
1. Behavioral differences: For example, species might feed at different times of the day (diurnal vs. nocturnal feeding).
2. Spatial differences: Species might forage or live in different parts of the same habitat, such as different heights on a tree canopy. A classic example is MacArthur's warblers, where five closely related species of warblers are able to coexist on the same spruce tree by foraging in different zones of the tree.
3. Morphological adaptation: Over time, species may evolve physical differences (such as different beak sizes in Darwin's finches) that allow them to specialize in different sizes or types of food, a phenomenon closely linked to character displacement.

Let's briefly look at the other options to understand why they are not the primary mechanism evolved for survival in this context:
- Competitive release: This describes the expansion of a species' niche or geographical range when a competing species is removed. It is a response to the absence of competition, rather than a mechanism evolved to survive ongoing competition.
- Mutualism: This is a type of symbiotic interaction where both species benefit from each other, which is the opposite of competition.
- Predation: This is an interaction where one organism (the predator) kills and eats another (the prey), which is a trophic interaction rather than a direct evolutionary mechanism to resolve niche overlap between competitors.