Answer:
oxygen-13
Step-by-step explanation:
Consists of 8 protons and electrons and 5 neutrons
 
        
             
        
        
        
Answer:A
Step-by-step explanation:
 
        
             
        
        
        
The number of viruses was 4000 times greater than number of protozoa.
Step-by-step explanation:
Given, 
Number of protozoa = 
Number of viruses = 
Let,
x be the number of times number of viruses is greater than number of protozoa.
Number of viruses = Number of time * Number of protozoa

Dividing both sides by 

The number of viruses was 4000 times greater than number of protozoa.
Keywords: division, scientific notation
Learn more about division at:
#LearnwithBrainly
 
        
             
        
        
        
It will be really a good answer for this 13.20