Answer:
Difficulty
Explanation:
Space exploration was the last thing the world could have thought of dabbing into because the idea of moving away from the earth and flying in the sky wasn't even an easy one for man, hence the difficulty attached with going into other planets was a big success.
Many trials were made before the eventual success experienced, this many difficulties man overcame is what is meant by barrier in this sense.
I think a is the best one
Answer:
D
Explanation:brainliest please
Answer:
Explanation:
A because its a way of expressing like ''he extolled the virtues of the Russian peoples" hope this helps
