Question - All of the oxygen on the earth comes from Answers:
1. producers releaseing it as a a product of photosynthesis

2. the clouds making it when the earth formed

3. heterotrophs breathing it out into the atmosphere

Based on anatomical similarities, to which modern animal is dr. digger’s creature most closely related?

10. in which phase will crossing-over occur? a. mitosis b. metaphase ii c. prophase i d. meiosis ii

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.