Why are fossils of early life on Earth rarer than fossils of ...

[sam.t96]

Why are fossils of early life on Earth rarer than fossils of plants and animals from the past few hundred million years?
 
  A) We find fossils in sedimentary layers, and no sediments were deposited until just a few hundred million years ago.
  B) Life was far less abundant prior to a few hundred million years ago.
  C) Early organisms were microscopic and lacked skeletons and other hard structures that are most likely to be fossilized.
  D) Fossils could not form before there was oxygen in the atmosphere.

Question 2

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.
 
  What will be an ideal response?

[JaynaD87]

Answer to Question 1

C

Answer to Question 2

Tom is on the main sequence, while Jerry is a supergiant. They both have the same surface temperature since they have the same spectral type, but since Jerry is much more luminous, Jerry must be much bigger in size.

[sam.t96]

Both answers were spot on, thank you once again

[JaynaD87]

Great! Please up vote