Science Glossary

• root hairs - specialised cells on the outer surface of a root, which absorb water and mineral ions from the soil
• xylem vessels - long, hollow tubes through which water moves in a plant; they are made up of dead, empty cells joined end to end
• transpiration - the loss of water vapour from a plant's leaves
• wilted - collapsed; plant leaves wilt if they are short of water
• bladder - organ where urine is stored
• excretion - getting rid of waste materials that have been inside the body
• excretory system - the organ system that include kidneys, ureters, bladder and urethra
• kidneys - organs that filer the blood, removing urea and other unwanted substances from it and forming urine
• renal - to do with kidneys
• urea - a waste substance made in liver cells from unwanted proteins
• ureter - a tube that carries urine from a kidney to the bladder
• urethra - a tube that carries urine from the bladder to the outside
• urine - a liquid made by the kidneys; it contains urea dissolved in water
• fetal - to do with to do with a fetus
• fetus - a young animal developing inside the uterus