Because the user can draw directly to the screen, light pens are used by graphics artists, though they are not as accurate as digitizing tablets. The pen works with CRT monitors but is not as compatible with projectors, LCD screens and other display devices.
THE DEFINITION OF NUTRIENTS. The definition of nutrients is a substance that provides nourishment for growth or metabolism. Plants absorb nutrients mostly from the soil in the form of minerals and other inorganic compounds and animals obtain nutrients from ingested foods. THE SIX ESSENTIAL NUTRIENTS PEOPLE NEED.
A limiting nutrient is a nutrient necessary for plant growth, but available in a concentration insufficient to support continued growth. Once supply of this nutrient is exhausted, plant growth ceases regardless of other remaining nutrient quantities. Any nutrient can become a limiting nutrient in an ecosystem. For algae, the most obvious limiting nutrients are nitrogen, certain metals and phosphorus. Nitrogen removal is an expensive process, involving high energy and chemical costs and specialised equipment.