Read the text and complete the sentences with the right prepositions. Answer the question below the text.
Choose the correct option.
In 1984, the ALH8 4001 meteorite was discovered in the Allan Hills region of Antarctica. But it wasn't until 1996 that this lump of rock would gain significance. A group of scientists, led by David McKay from NASA's Johnson Space Center, assured the scientific community [of|on|for|about] finding signs of Martian life within the meteorite.
Studies of the meteorite showed that originally it was formed 4 billion years ago on Mars and it drifted through the Solar System until 13,000 years ago when it was captured by Earth's gravity and landed in Antarctica. NASA geochemists who studied the meteorite saw microscopic shapes inside it: worms and sausages that looked just like Earth bacteria, except much smaller. They insisted [of|about|for|on] finding the evidence of life on Mars because it is believed that 4 billion years ago Mars was abundant in water, an essential resource for life.
Sceptics fought the evidence with the view that the patterns and materials within the meteorite could have been formed from non-biological processes. The scientific community complained [to|on|about|for ] the study failure and accused David McKay [of|for|about|on] the wrong interpretation of the study results.
Write one number in a gap.
What led scientists to believe that life existed on Mars?
A non-biological process that took place inside the meteorite.
The traces of organisms inside the meteorite.
The composition of water found inside the meteorite.
Answer: [ ]