This passage could be entitled ______.

A．The environment crisis will not be solved unless we stop using virgin materials.
B．In scientific research, a higher priority should be given to understanding all living systems.
C．Exploration of outer space will finally lead to an improvement on human living conditions.
D．U.S. high-technology companies are applauding this new twist in scientific research.

A．She had devoted herself to skiing during high school and proved herself a very promising skier.
B．She had been a member of the U.S. Olympic ski team.
C．She was seriously wounded in the pre-Olympic tryouts.
D．Her career as a skier was destroyed in 1955.