Certain species of fish are unsafe to consume in high quantities because these fish

The given blank can be filled with comprises higher amount of  methylmercury.

Explanation:

Mercury refers to a mineral that prevails naturally in the surroundings. In supplementation, ample of tons gets discharged into the air every year via wastes and pollution. The methyl gets transformed into methylmercury, that is, the organic mercury compound, that is, a poisonous component.  

The fish one consumes unfortunately also comprises the toxin methylmercury. In the streams and oceans, methylmercury can get gather and can also get absorbed in the food chain, as all the fish captivates all the mercury of the organisms that they consume. Due to this, the largest and the oldest fish like sharks and swordfish comprises the highest ratio of methylmercury in them.  

Some of the fishes like swordfish, shark, tilefish, and king mackerel are unsafe to consume in larger quantity as they constitute a higher amount of toxin methylmercury.  

i am sorry but i need more information and a picture.

b) charles darwin i learned that last year!