The double membrane. It's theorized that chloroplasts used to be their own single-celled organism in the environment (and therefore with its own membrane). Then, the theory states, a larger cell took in the chloroplast by endocytosis, which involves surrounding the chloroplast in the large cell's own membrane. The chloroplast would then have two membranes surrounding it. This is similar to the thinking for mitochondria becoming an organelle as well. Hope this helps! :)
        
             
        
        
        
The correct answer for the blank is: Oatmeal.
I hope that helped you! c:
        
             
        
        
        
Vaccines, wash your hands, and condoms. There might be more but I think that’s it, hope this helped!
        
                    
             
        
        
        
Markets will want to buy it since it is a special produce.
        
             
        
        
        
A. "In the distant future, we're all going to be crushed"
Explanation - 
Oscillating Universe Theory combines the big bang theory and the big crunch theory. This theory states that the Universe does not have any end and it would undergo various epochs during this process. 
It mentions that the Universe expands and contract where it becomes small and dense and will lead to a new beginning that will have a different property than the old universe. Some day, the universe is going to shrink and crush.