Remediation plans have been moderately successful. The 1970 fishing ban has been lifted, but some restrictions remain. Consuming fish caught in Onondaga Lake is limited due to potentially dangerous levels of mercury stored in the fish tissue. The diagram and table below show the mercury concentration levels in a food chain of a typical lake ecosystem. Mercury is measured in the amount of nanograms per kilogram (ng/kg). 

If burning fossil fuels causes climate change, what other sources of energy could we use? Do they have any trade-offs?

Two new wind turbines have recently been built within the Eiffel Tower in Paris. The power that these turbines generate will be enough to power the entire first floor of the tower, including the restaurants, shops, and exhibits. A benefit of using wind power as an alternative source of energy is that it

(A) is nonrenewable, so additional resources will be depleted by tower businesses

(B) is renewable, so it will decrease the environmental impact of the tower businesses

(C) increases the use of resources that cannot be renewed in the future

(D) decreases the amount of fossil fuels available for future generations

Limitation: A drawback or something that makes an option less effective. Often the negative part of a trade-off. 

Example from yday: Putting water ballast filters on ships will reduce invasive species, but a limitation would be that the filters are expensive to install.