Answer - It is a Great Concern because microbes such as a hydra can consume some of that mercury which then a shrimp can consume that microbes which then transfer into the mouth of a trout which then when humans fish they consume the fish which later we get Mercury poisoning. 
Reasoning - There are more concern but these are a few and some reasoning. 
 
        
        
        
The correct answer for this question would be C) At seafloor spreading centers or the third option.
        
             
        
        
        
Answer:
100%
Explanation:
the only possibilities from HH and hh are: Hh Hh Hh Hh
 
        
             
        
        
        
The Answer is  B Latitude measures North and south,; Longitude measures East and west
This is the Reason I think its B is because Latitude implies the geographic coordinates that determine the distance of a point, north-south of the equator. Longitude alludes to the geographic coordinate, which identifies the distance of a point, east-west of the Prime Meridian.
<em>Hope this helps and can i please have brainliest ?</em>