18. Viruses are considered because they can not perform the characteristics of life without a
19. Viruses are made of two basic compounds,
and a
made of protein.
20. A virus infects a cell by injecting
into a cell.

Which plate boundary causes plates to collide forming mountain ranges, volcanoes, and island arcs? give an example of this type of plate boundary. 2. at which plate boundary do rifts and mid-oceans ridges form? give an example of this type of plate boundary. 3. at which plate boundary do plates slide past each other while moving in opposite directions? give an example of this type of boundary.