Polar bears are listed in red as they are belong to Endangered Species. These species are gonna extincting due to gradual changes by environmental factors.
 
        
                    
             
        
        
        
A Only one variable changed
        
             
        
        
        
A, I believe. Because after collecting you need to analyze in order to do many other steps. Also all the other answers are something before collecting data
        
                    
             
        
        
        
The main force that causes filtration in a nephron is... glomerular hydrostatic pressure.
I hope this helped:)
        
             
        
        
        
Let us look at the what, why and how of studying extreme places like the deep earth and the deep space. Scientists need to figure out as to 'what' they want to look at such places, be it a new exotic creature or bio-genesis (birth of life). Unless there are several testable hypothesis constructed, such a study cannot begin. The 'why' aspect deals with the purpose of such research and expeditions. Is it of any use to the humans, or will it improve our current understanding of a phenomenon? The 'how' aspect deals with the technology and the economic assistance that can help in undertaking such a research. All these are the challenges that needed to be thoroughly considered to make such a research or expedition possible.