By dating the rocks in the ever-changing crust, as well as neighbors such as the moon and visiting meteorites, scientists have calculated that Earth is 4.54 billion years old, with an error range of 50 million years.
 
        
                    
             
        
        
        
Answer:
Albert Freeman Africanus King (18 January 1841 – 13 December 1914) was an English-born American physician who witnessed the assassination of Abraham Lincoln on 14 April 1865. He was a bystander physician who was pressed into service during the assassination.
 
        
             
        
        
        
I know accurate is really close or exact but the reproducible ive never heard
        
                    
             
        
        
        
Answer:
used to observe small objects, even cells
Explanation:
The image of an object is magnified through at least one lens in the microscope.
 
        
             
        
        
        
Answer: Adenina 
Explanation:
Base nitrogenada: una molécula que contiene nitrógeno y tiene las propiedades químicas de una base. Las bases nitrogenadas en el ADN son adenina (A), guanina (G), timina (T) y citosina (C). Las bases nitrogenadas en el ARN son las mismas, con una excepción: adenina (A), guanina (G), uracilo (U) y citosina (C).