Answer:
B. The Edict of Milan helped spread Christianity by allowing all religions in Rome.
D. He believed that locating the capital in an area that had more trade and business would ensure the future of the empire.
Explanation:
The great achievement of reign of Constantine is the Edict of Milan that helped in spreading of Christianity in Rome. He was the first roman emperor which profess the religion of Christianity in the year 313. This proclamation legalized the Christianity religion and allowed all people of Rome the freedom of worship throughout the empire. Constantine move the capital of the Roman Empire because he wanted that the capital will become the economic, cultural hub and center of the east.
 
        
             
        
        
        
Polymers are made of individual subunit called monomer.
<u>Explanation:</u>
Polymers are lengthy chains built up of replicating molecular subunits, named monomers. The term polymer becomes from poly- (many) and -mer (part). A polymer may be a real or manufactured macromolecule composed of recurring units of a smaller molecule (monomers). The term monomer comes from mono- (one) and -mer (part). 
 Monomers make polymers by creating chemical bonds or confining supramolecular by a method called polymerization. Examples of polymers comprise plastics like polyethylene, silicones. Polymerization is the method of covalently bonding the smaller monomers into the polymer. While polymerization, chemical groups are failed from the monomers so that they may join together.
 
        
                    
             
        
        
        
The question doesn't have choices. It would be better to have one.
        
                    
             
        
        
        
Oxygen entered the Earth's atmosphere after the appearance of the Great Oxidation Event (Great Oxygenation Event). The Great Oxidation is the first mass extinction on Earth.
The Great Oxidation lasted 2.4 to 2.0 billion years ago.
Oxygen appeared on Earth thanks to cyanobacteria using photosynthesis.
 
        
             
        
        
        
Answer:
Human heart is myogenic becoz it have the tendency to generate impulse by itself. The upper right auricle wall of heart has sino atrium node or SN node which helps in generation of impulse without any external stimulus.