In severe cases, the viral infection causes a high fever, bleeding into the skin, and necrosis (death) of cells in the kidney and liver. The damage done to the liver from the virus results in severe jaundice which yellows the skin. Hence, the yellow in yellow fever..
filter definition: The definition of a filter is something that separates solids from liquids, or eliminates impurities, or allows only certain things to pass through. (noun) A Brita that you attach to your water faucet to remove impurities from you...
A plant filter is a simple channel or small filtration pond through which water from the pond is fed at a relatively slow rate. Fast-growing plants (efficient nutrient removers) are grown within this channel in planting baskets or are free-floating, such as water lettuce or water hyacinth.