In an undisturbed stack of rock layers, each containing fossils of once-living organisms, where would some evidence of the most ancient life forms most likely be found? a. at the top of the stack b. near the top of the stack c. in the middle of the stack d. at the bottom of the stack

Explain why scientists use shared characteristics to make cladograms.

Compare and contrast the bohr model and the electron cloud models of the atom.

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.