Class 30, ICA #26, November 2.

There were 3 clicker questions. 
You get 1 mark for answering each question.
I didn't count getting it right or not.

The clicker questions count for a total of 3 points toward your
course grade, so your points for the day = # of marks * (3/3).



Clicker Question #1: Suppose there had been no major
impacts in the last 65 million yeras. What might
Earth be like today?

A. Mammals would have evolved differently; humans might
not be here.


Clicker Question #2: 250 million years ago, there was another
large extinction event that killed off 90% of all species
on Earth. Would you expect to find a crater?

C. No - the crater would have eroded away by now.



Clicker Question #3: If something like Tunguska happens every
~100 years, how come we haven't heard about it [in previous
events, say 200 or 300 or 400 years ago]?


C is the current best guess, though one could argue
that A and B are possible answers.