The theory of a land bridge between South America and Africa as an explanation for similar fossils on the two continents is not supported today because

When the volume and number of particles of a gas are constant which of the following is also constant

Which of these best describes an ionic bond?

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.