Most organisms breathe using oxygen or carbon dioxide. where do these gases come from on land?
air
offspring
homeostasis
shelter

Suppose the universe were completely empty except for one object-a solid sphere moving through space of 100 km/s. what sort of path would the object be moving in? explain your answer

The twister and runaway train are two coasters at the same amusement park. both coasters start at the same height. the coaster for the twister is twice the mass of the coaster for the runaway train. which roller coaster has greater gravitational potential energy at the start of the ride?

What human activity increases beach erosion?