What percentage of ozone is contained in the stratosphere?
a. 10%
b. 50%
c. 80%
d. 90%

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.

What are two ways that harvesting algae from the ocean may benefit human society? how might the harvest of algae negatively impact the ocean communities where that algae grows? how could this be prevented?

Which worm has eyespots that are used to detect light? a fluke b marine worm c planarian d tapeworm