Hello.Mr. Kevyn. 

I want some additional explanation for question 5. 

First, I was confused between A and B.

I found the reason why B can't be the answer and I ask you to check it!

The passage 2 says.

Why did it occur so late in the history of Earth?  The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself.  

Looking from the context, I had figured,

'The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself'

->' Origin of Multicellular form(=animal) should take less time to emerge compared to the origin of life itself'.

Therefore, B can be the answer. 

Is this correct? 

Thank you!