<span>In a dichotomous key you named them by their traits while in a branching diagram it already has the name and it's traits.
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Hope this helps :)</span>
        
             
        
        
        
Answer:
There is no video but ecological relationship will be defined on a general note and it is not always beneficial to organisms.
Explanation:
In an ecosystem, organisms of the same or different species tend to interact with one another. This interaction is referred to as ECOLOGICAL RELATIONSHIP between the involved organisms. An ecological relationship can be of different types depending on the effect. 
SYMBIOSIS is an ecological relationship between two organisms that interact together. SYMBIOSIS can either be mutualistic (both organisms benefit), parasitic (one organism loses and one gains), or commensalistic (one organism benefits and one neither benefits or loses). Another ecological relationship is PREDATION, where one organism called the PREDATOR feeds on part or all of another organism called PREY in order to obtain energy. 
As stated above, some of the organisms involved in an ecological relationship benefits while others lose. Hence, it is not always a beneficial relationship to organisms.
 
        
             
        
        
        
Answer:
Changes in gene expression
Explanation:
 
        
                    
             
        
        
        
Isobars represent adjusted atmospheric pressure. This removes pressure discrepancies caused by the location's relation to sea level or altitude. Isobars are also adjusted when necessary so that they never cross or touch. Weather maps with isobars give pressure information at a glance. They also give an approximation of wind direction because wind moves from high-pressure areas to low-pressure areas as large air masses move through the pressure differential.