The sample appears to have gone through 3 half-lives
1st half life: 1000 to 500 g
2nd half life: 500 to 250 g
3rd half life: 250 to 125 g
The duration of a half-life, therefore, can be inferred to be 66 ÷ (3) = 22 days. 
After a 4th half life, there will be 125÷2= 62.5 g. 
At this point, an additional 22 days will have passed, for a total of 88 days.
Answer is C. 
        
             
        
        
        
Same for #1 I have to say the same thing
        
             
        
        
        
Answer:
Yes,earth has an electric field