Mark the letter A, B, C, or D to indicate the correct answer to each of the following sentences.

Burning yard waste releases mold spores, soot, and other contaminants that can aggravate allergies and cause ____ problems.

Modern day agriculture practices ____ chemical products like pesticides and fertilizers to deal with local pests.

Waste from industrial and agricultural ____ pollutes the water that is used by humans, animals and plants.

The number of inhabitants on the planet ____ arriving at unsustainable levels as it confronts deficiency of assets like water, fuel and food.

Land pollution can have huge environmental impact ____ the form of air pollution and soil pollution which in turn can have adverse effect on human health.

To help save the environment, try ____ energy and water consumption, changing your eating and transportation habits to conserve natural resources, and adapting your home and yard to be more environmentally friendly.

At present, timberlands cover 30% of the area, but wooded areas are being lost ____ a regular basis because people are looking for homes, food, and materials.