Amagnet is
a) any material that repels metals.
b) any material that attracts iron
c) and material that attracts helium

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

In the reaction between a crushed antacid tablet and vinegar what gas is emitted

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?