Choose the best answer

Scientists believe that Mars also __________seasons just as the Earth does.

Choose the best answer

The scientists believe that there might be some planets to .................. human life.

Choose the best answer

Mercury .................. after the Roman God Mercury.

Choose the best answer

The prerequisite condition for a/an .................. planet is water supplies, appropriate temperatures and breathable air.

Choose the best answer

Mercury is very close to the sun, and it is very hot. Therefore, there .................. not be life on it.

Choose the best answer

An astronaut has to wear a spacesuit ___________it may be very cold in space.

Choose the best answer

The UFO ………. on a grassy area.

Choose the best answer

Scientists have been trying to find ___________ of aliens.