The picture shows three connotations of biodiversity. Please tell me what these three connotations are and what is the relationship between them.

Item a in the figure represents different genetic genes of individuals with different traits in a rabbit population, indicating the diversity of genes; Rabbits with different gene banks and other creatures on the grassland, such as snakes, birds and plants, constitute the diversity of biological species in the grassland ecosystem (item B in the figure); Grassland ecosystem, river ecosystem, forest ecosystem and other types of ecosystems together form a certain regional landscape, showing the diversity of ecosystems (item C in the figure). As can be seen from this figure, on the one hand, the essence of biodiversity is gene diversity, and gene diversity determines biodiversity; The diversity of biological species constitutes different ecosystems; On the other hand, the fundamental measure to protect genetic diversity is to protect the diversity of living environment and ecosystem.

So the answer is: biodiversity usually has three main connotations, namely, biodiversity, genetic diversity and ecosystem diversity. On the one hand, the essence of biodiversity is genetic diversity, which determines biodiversity; The diversity of biological species constitutes different ecosystems; On the other hand, the fundamental measure to protect genetic diversity is to protect the diversity of living environment and ecosystem.