In situ conservation refers to the preservation of species in their natural habitats, which is a comprehensive approach that involves protecting entire ecosystems. This method aims to maintain and recover populations of species within their natural environments, where they have evolved. The correct answer to the question of what in situ conservation refers to is "Protect and conserve the whole ecosystem.
Explanation:
In summary, in situ conservation's emphasis on protecting whole ecosystems encapsulates a comprehensive approach to biodiversity conservation.
A biologist surveyed islands of different sizes and consolidated the results in the form of the data given below. Study the data carefully and answer the questions that follow.
Based on data (Birds decline, Plants % decline, Area decline), interpret two reasons for change in the population of migratory birds. 
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below:
The term ‘biodiversity’ is derived from the two words- ‘bios' which means life and ‘diversity’ i.e, differentiation or variation. Edward Wilson, the sociobiologist was the first to popularise the term ‘biodiversity’ in the year 1992. The term implies the occurrence of various plants and animals along with their variants such as biotypes, ecotypes and genes on earth. In our biosphere, the immense diversity or heterogeneity remains not only at the species level but also, at every level of biological organization that ranges from macromolecules in the cells to biomes.
Biodiversity and Conservation is a topic covered under the fifteenth chapter and Unit 5 of NCERT class 12 biology.