Answer:
That would be A 
Explanation:
Adding "in" to the word substantial would result in a word meaning the opposite. 
 
        
             
        
        
        
#3 out of all of them. It has to be the best
        
             
        
        
        
Hey there!
I believe the answers you wrote are already correct, except for #3 because the verb, had. I think both might be correct in this situation. Keep up the great work!
Have a great day :)
 
        
             
        
        
        
Answer:
By experiencing it directly
Explanation:
He leaves the astronomer's class to go look at the stars himself, which he found to be a better experience then just listening to someone talk about them.