The retreat of the shallow seas of the paleozoic left much of virginia exposed during the permian and mesozoic. in central virginia, trace fossils, including footprints have been found. a) dinosaur b) horse c) human d) mastodon

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.

The student repeated the experiment using a higher concentration of acid. the same volume of acid and the same mass of magnesium ribbon were used. what volume of hydrogen gas would have been produced after 60 seconds?