The correct answer is option 'C': Insensitivity to our environment.

Explanation:
Insensitivity to our environment refers to the lack of awareness and concern for the impact of human activities on the environment. This insensitivity leads to actions that harm the diverse flora and fauna of the planet.

1. Destruction of habitats: Insensitivity to our environment often results in the destruction of natural habitats. Forests are cleared for agriculture, urbanization, and industrialization, leading to the loss of habitat for many plant and animal species. This destruction disrupts ecosystems and threatens the survival of various species.

2. Deforestation: Insensitivity to our environment also contributes to deforestation. Trees are cut down for timber, agriculture, and other purposes, causing the loss of important ecosystems and habitats. Deforestation reduces biodiversity and negatively affects the flora and fauna that rely on forest ecosystems.

3. Overexploitation: Insensitivity to our environment leads to the overexploitation of natural resources. This includes overfishing, illegal hunting, and the unsustainable harvesting of plants. Overexploitation can result in the depletion of certain species and disrupt the delicate balance of ecosystems.

4. Pollution: While pollution is not the correct answer in this case, it is worth mentioning that insensitivity to our environment also contributes to increasing pollution levels. Pollution from various sources, such as industrial waste, agricultural run-off, and improper waste management, can harm both plants and animals. It contaminates water bodies, degrades air quality, and affects the health and survival of species.

5. Climate change: Although global warming is not the correct answer, it is important to note that insensitivity to our environment also contributes to climate change. Activities such as deforestation, burning of fossil fuels, and the release of greenhouse gases are major contributors to climate change. Climate change has significant impacts on ecosystems, altering temperature and precipitation patterns, and affecting the distribution and survival of plant and animal species.

In conclusion, insensitivity to our environment plays a significant role in the threat faced by the diverse flora and fauna of the planet. It leads to the destruction of habitats, deforestation, overexploitation, and ultimately disrupts ecosystems and biodiversity. It is essential for individuals and societies to become more aware and sensitive to the environment to ensure the protection and conservation of our valuable natural resources.