Answer: Classified as a theory.
Explanation: The dictionary definition of theory is a system of ideas that are used to logically explain something. It also says that they are also based off of something not entirely connected to the thing the theory is being made about.
Because the idea that the universe has expanded explains such a large number of observations, which in turn leads to more predictions and therefore more observations that support it, this becomes your system of ideas. Because this system was based off of the aforementioned observations in the first paragraph, this proves that it is best classified as a theory.
 
        
             
        
        
        
It was robert hooke if i’m correct
        
                    
             
        
        
        
Answer:
Primary succession is the orderly and predictable series of events through which a stable ecosystem forms in a previously uninhabited region. Primary succession occurs in regions characterized by the absence of soil and living organisms.
 
        
             
        
        
        
A 
Why?:
because i was asking myself what else would make a abyssal plain? and i decided it was a, i WAS gonna say D but i thought really hard about it (plz mark me brain list if it's right is not it's okay and i hope i'm right!) :3