Answer:
They fight against infections and disease.
Explanation:
 
        
                    
             
        
        
        
Explanation:
we all find ourselves confronted with the age-old question: 
what happens when you fall into a black hole?
You might expect to get crushed, or maybe torn to pieces. But the reality is stranger than that.
The instant you entered the black hole, reality would split in two. In one, you would be instantly incinerated, and in the other you would plunge on into the black hole utterly unharmed.
Hope this helps you.. Good Luck 
 
        
                    
             
        
        
        
Answer:
D. Geologist compare the observed abundance of naturally occurring radioactive isotopes and their decay products using decay rates.
Explanation:
Radioactive dating is the method in which radioactive isotopes are employed to evaluate the age of rocks and ores. There are many complex radioisotopes utilized for radioactive dating is like Potassium, Uranium, and Carbon. Radioactive dating operates on the system that a radioactive isotope can fade into the constant daughter nuclei at a steady rate. Geologist commonly uses the system for half life. Half-life is the time needed for half of the radioactive element to decline. This is fixed for a selective element.