The Human Body
$200This organ pumps blood throughout the body.
$400This organ, the body's largest internal organ, filters blood, stores nutrients, and produces bile.
$600These 206 structures make up the adult human skeleton.
$800This red protein in blood carries oxygen and contains iron.
$1000This part of the brain controls balance and coordination, at the back of the skull.
Chemistry
$200H2O is the chemical formula for this substance.
$400This gas, with symbol O, is essential for human breathing.
$600This chart organizes all the chemical elements by atomic number.
$800This element, symbol Au, is a precious yellow metal.
$1000A substance with a pH below 7 is classified as this.
Space
$200This star is at the center of our solar system.
$400This is the closest planet to the Sun.
$600This planet is famous for its prominent rings.
$800This 1969 NASA mission first landed humans on the Moon.
$1000This galaxy is the one that contains our solar system.
Physics
$200This force pulls objects toward the Earth.
$400This form of electromagnetic energy travels in visible wavelengths and lets us see.
$600This scientist developed the theory of relativity and E=mc².
$800This scientist described the three laws of motion and universal gravitation.
$1000The speed of light in a vacuum is roughly this many kilometers per second.
Life Science
$200Plants make their own food through this sunlight-powered process.
$400This molecule carries genetic instructions and has a double-helix shape.
$600This is the basic structural unit of all living things.
$800This scientist proposed the theory of evolution by natural selection.
$1000This 'powerhouse of the cell' generates energy through respiration.
Earth Science
$200This water cycle process turns liquid water into vapor.
$400These giant moving sections of Earth's crust cause earthquakes when they grind and shift.
$600This scale measures the magnitude of earthquakes.
$800This layer of gas high in the atmosphere protects Earth from UV radiation.
$1000This hard, innermost layer of Earth is made mostly of solid iron and nickel.