"C. Ecosystem"
An ecosystem is described by the interaction between living organisms in a given area, interacting with others, and non-living aspects of the environment where they are in. By considering the living place of a woodchuck, what they eat, and where they feed, we are talking about an ecosystem.
The answer is D because A,B,C all what cause damage
Answer:
Option (A).
Explanation:
The element mercury can persist in the environment and proves to be harmful for the living organism. The mercury persist in the lower organism and transfer to the higher organism by the process of biological magnification.
The compounds of methyl mercury are not harmful. The methyl mercury compound cannot cross the blood-brain barrier and does not affect the individual.
Thus, the correct answer is option (A).
I'll include the link so you can find some answers on there :) https://quizlet.com/136508585/planet-earth-freshwater-flash-cards/
If this one doesn't include all of the answers, just google the name of your worksheet and there will most likely be a Quizlet on it. If not, google one question from the worksheet and you may come across a Brainly or Yahoo question with other questions (and answers) included. Good luck!!