The answer is atrial depolarization. The P wave of a normal electrocardiogram specifies atrial depolarization.  In addition, depolarization happens in the four compartments of the heart which is both atria first and in both ventricles. The sinoatrial or as called as SA node on the wall of the right atrium starts depolarization in the right and left atria that can cause the contraction in which it is symbolized by the P wave on an electrocardiogram.
        
             
        
        
        
False,  it was 1670 when they first saw bacteria.
        
                    
             
        
        
        
<span>A. If one essential nutrient within an ecosystem runs out, primary productivity will be limited.
A specific nutrient is need for every organism in the ecosystem. If this particular nutrient is diminished within the ecosystem then cellular processes will decreases and a great number of specie will die. </span>
        
             
        
        
        
Answer:
field studies
Explanation:
The documentation and collection of descriptive details of events in nature such as amounts, sizes, colors, smell , behavior, texture e.t.c are all categorized as field studies. 
It involves the gathering of raw data outside a laboratory. 
- Often times, based on the needs of an experiment, it is desirable to corroborate laboratory studies with field evidences. 
- The approach in gathering such data varies from discipline to discipline. 
- Most field sampling are usually done in an uncontrolled environment.