The Four ChambersAnatomy and PhysiologyThe HeartAnatomy of the HeartThe Four ChambersThe Heart's Own BloodECG: Measuring a Beat So why do you need four chambers if three worked just fine for…
WHAT IS A NERVE? HOW DO NEURONS WORK? ARE ALL NEURONS THE SAME? WHAT IS A REFLEX ACTION? FIND OUT MOREThe brain, nerves, and spinal cord make up the nervous system. It processes information from the…
WHAT ARE SPACE STATIONS USED FOR? HOW ARE SPACE STATIONS BUILT? INTERNATIONAL SPACE STATIONFIND OUT MOREIn a space station, a large crewed spacecraft orbiting Earth, astronauts can live and work in…
WHAT KINDS OF TASKS DO ASTRONAUTS PERFORM? HOW DO ASTRONAUTS TRAIN FOR THEIR MISSIONS? EXTRAVEHICULAR ACTIVITIESFIND OUT MOREAnyone who travels in space is called an astronaut. The Russians call…
Fever and Ague: Malaria's SymptomsMalariaIntroductionA Nasty ParasiteFever and Ague: Malaria's SymptomsA Frustrating, Yet Curable, DiseasePrevention and Cure People infected with malaria typically…
The Great DivideAnatomy and PhysiologyThe Nervous SystemThe Great DivideSupport StaffNeuronsConnecting with SynapsesYou've Got Potential The nervous system can be divided two ways, anatomically…
(Encyclopedia) Dreiser, TheodoreDreiser, Theodoredrīˈsər, –zər [key], 1871–1945, American novelist, b. Terre Haute, Ind. A pioneer of naturalism in American literature, Dreiser wrote novels…
SKYLAB IN ORBITMISSION TO MIR, 1995INTERNATIONAL SPACE STATIONFIND OUT MOREA space station is a spacecraft designed to stay in orbit for many years. Conditions inside are carefully controlled:…
They were once called chiffoniers, then ragpickers, then junk dealers; now they are secondhand clothes dealers. Since biblical times, people have worked for food, clothing, and shelter. They still…
