Farm Pollution

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Across
  1. 3. A colorless, odorless and nonreactive gaseous element that forms about 78 percent of Earth's atmosphere. Its scientific symbol is N. Nitrogen is released in the form of nitrogen oxides as fossil fuels burn.
  2. 4. Nitrogen, phosphorus and other plant nutrients added to soil, water or foliage to boost crop growth or to replenish nutrients that removed earlier by plant roots or leaves.
  3. 6. The process by which a body of water becomes full of nutrients, which then stimulates the excessive growth of plants and algae.
  4. 9. A chemical containing one atom of phosphorus and four atoms of oxygen. It is a component of bones, hard white tooth enamel, and some minerals such as apatite.
  5. 12. A part of an experiment where there is no change from normal conditions. The control is essential to scientific experiments.
Down
  1. 1. A vitamin, mineral, fat, carbohydrate or protein that a plant, animal or other organism requires as part of its food in order to survive.
  2. 2. A highly reactive, nonmetallic element occurring naturally in phosphates. Its scientific symbol is P. It is an important part of many chemicals and structures that are found in cells, such as membranes, and DNA.
  3. 4. A leaf or leaf-like structure that itself consists of many almost-leaf-like appendages. Good examples include the leafy structures of palms and ferns.
  4. 5. The water that runs off of land into rivers, lakes and the seas. As that water travels over land, it picks up bits of soil and chemicals that it will later deposit as pollutants in the water.
  5. 7. Single-celled organisms, once considered plants (they aren’t). As aquatic organisms, they grow in water. Like green plants, they depend on sunlight to make their food.
  6. 8. Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.
  7. 10. A poison produced by living organisms, such as germs, bees, spiders, poison ivy and snakes
  8. 11. (in microbiology) The rapid and largely uncontrolled growth of a species, such as algae in waterways enriched with nutrients.