Which factor is essential for the survival of many species and is threatened by human activity?

Natural habitats are essential for the survival of many species because they provide the necessary resources and environment that organisms need to thrive, including food, shelter, and mating opportunities. These habitats are complex ecosystems, often comprised of various interacting species, and any alteration or destruction can lead to a loss of biodiversity. Human activities such as urban development, deforestation, pollution, and agriculture significantly threaten these natural habitats by fragmenting them, altering their characteristics, or completely destroying them.

While the other factors—oxygen levels, water availability, and soil composition—are also critical for survival, they are often influenced by the state of natural habitats. For example, aquatic habitats are crucial for maintaining water quality, and terrestrial ecosystems play a significant role in oxygen production through photosynthesis and nutrient cycling through soil interactions. Thus, maintaining natural habitats is foundational to ensuring the overall health of ecosystems, which directly supports diverse species.