How do prions, which are misfolded proteins, infect organisms?

In which state was more than 100 billion tons of coal mined in 2005?

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.

What is it called when lava when it erupts from the surface through volcanoes.