<u>Answer:</u>
Approximately, the oldest stromatolites are 3.6 billion years old on earth.
<u>Explanation:</u>
- Stromatolites is not only oldest earths fossil but conspiracy in that they are singular visual portal in deep time on earth. 
- It is defined as laminated accumulation structure that is they stick up above sea floor . 
- Stromatolite buildings includes oldest fossils which are 3.5 billions old when the earth were too unfriendly to support life.
- The study of  fossil age, evolutionary, method of formation are known as paleontology. 
- These specimens are considered as old fossils which are around 3.4 to 4.1 billions years old.
 
        
             
        
        
        
DD in top left Dd in top right dd in bottom right 75% dimples and 25% no dimples
        
             
        
        
        
Toxins in the soil would enter through the root system first.
 
        
                    
             
        
        
        
It affects the environment by maybe causing pollution
        
                    
             
        
        
        
The nurse should obtain the specimen from the catheter.
One of the tests from urinalysis that frequently got contaminated is about infection. The area near the orificium of uretra is near the skin, so there will be microbes around it that can contaminate the sample. The contaminated sample will give a false positive and the result will show the urine are infected.
Taking the specimen from catheter will prevent that contamination, thus giving a better sample.