A．She is writing a competitive paper for a scholarship.
B．She is doing a research paper.
C．She missed the lecture.
D．She is planning to attend the scholarship award ceremony.
A．Why species don't avoid extinction by adapting.
B．Why species become extinct at the rate they do.
C．Why humans aren't extinct.
D．How many species aren't extinct.
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.