Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29.

PUSHING THE FRONTIERS OF SCIENCE
Humans have been thinking about the universe and (25) ______ what is out there for centuries, and ever since the space race of the ‘50s and ‘60s and the boom in technological developments, the belief that we might actually be able to venture into outer space has grown.
One of the main fascinations has been with our neighbouring planet, Mars. Some see the red star as hope for the survival of the human race (26) ______ this planet is thought of as a possible site for a human colony. Since the Italian astronomer Giovanni Schiaparelli first made map to document the surface of Mars in 1878, there have been (27) ______ speculations to whether the planet can support life. Schiaparelli believed that it already did. In fact, he put forward the idea that the channels (28) ______ he saw on the planet’s surface were not natural but created by an advanced race of Martians. It was not until scientists had access to more powerful telescopes that his theories were disproved. Today, man’s desire to (29) ______ the reaches of the galaxy doesn’t seem to be diminishing. One day, will we eventually be living among the stars?