What cell structure is made of a bilayer of phospholipids and
encloses all cells?

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a. control b. hypothesis c. procedure d. system

African penguins, which inhabit the coasts of southern africa, were classified as an endangered species in 2010. two significant threats to their survival are ecosystem damage from oil spills and overfishing by humans. overfishing depletes the food supply of african penguins. the best method to reduce the threat of overfishing would be to . the risk of oil spills could be reduced by increasing the use of , which should oil consumption. if an oil spill does occur, could be used to remove the oil so the ecosystem may more quickly recover.

Producing disposable grocery bags consumes resources. recycling disposable bags is a solution that can recover some of the resources used to make new bags. which of the following behaviors could further refine the solution? a. disposing of bags by burning them b. reusing bags whenever possible c. using bags at once so that they do not break d. using only nonrenewable materials to make new bags subject is environmental science for apex users