A.Because every species becomes extinct.
B.Because humans beings are powerful enough to kill other species.
C.Because of over-population.
D.Because human being is still a young species though it is exploiting the environment.
A.He thinks flies will take over the earth.
B.He thinks human will die off quite soon.
C.He thinks mass disease could be the next path to extinction.
D.He sees human beings as destructive.
A.A part of the free MIT OpenCourseWare.
B.A free computer programme by MIT and Harvard.
C.A Harvard-MIT platform of free online courses.
D.A free programme online for universities worldwide.