The correct answer is Option 4: Mankind`s over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.

The term "sixth mass extinction" or "sixth extinction" refers to the ongoing extinction event that is occurring on Earth, which is characterized by the rapid and widespread loss of species and ecosystems. This extinction event is believed to be caused primarily by human activities, including over-exploitation of natural resources, habitat loss and fragmentation, pollution, and climate change.

Human over-exploitation of natural resources has led to the depletion of many of the Earth`s resources, including fish stocks, forests, and minerals. This over-exploitation has also led to the extinction of many species, either directly through hunting or indirectly through the destruction of their habitats.

Habitat loss and fragmentation are major drivers of biodiversity loss. Human activities such as deforestation, urbanization, and agriculture have led to the destruction and fragmentation of natural habitats, which makes it difficult for many species to survive and reproduce.

Pollution, including air, water, and soil pollution, is also a significant threat to biodiversity. Polluted environments can lead to the death of many organisms, including microorganisms, insects, and larger animals.

Finally, global climate change is one of the most significant threats to biodiversity, as it can lead to changes in temperature, precipitation, and sea level, which can have severe impacts on many species and ecosystems.

All of these factors contribute to the ongoing mass extinction event, which is estimated to be occurring at a rate that is thousands of times faster than the natural rate of extinction. Without significant action to address these issues, the loss of species and ecosystems is likely to continue and accelerate in the coming decades.