7. Hva menes med masseutryddelse av arter, og hvor mange masseutryddelser har det vært på jorda før mennesket oppsto som art?
8. Hvor mange mennesker levde på jorda i 1925? Finn deretter ut hvor mange vi er akkurat i
dag, ved å søke på «world population clock». Regn ut hvor stor økningen har vært.

What kind of seafood would you expect to have the highest levels of mercury and why? kelp, because they use the sun to photosynthesize on the bottom trophic level. oysters, because they filter feed on plankton on a lower trophic level. small fish, because they eat plankton on a higher trophic level. sharks, because they feed on organisms on a higher trophic level.

Astudent drew the following flowchart to show the movement of nutrients. soil → roots → plants →? where does nitrogen go next? a. directly into nearby animals as nutrition b. directly into aquifers through condensation c. directly into the air through evaporation d. directly into nearby plants during fixation

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.