Please solve thus exercise

1.a) We often believe that the bats are the scariest creatures in the world.
b) Bats are the only mammals that have the ability to fly.
c) They have leathery membrane bodies made up of wings and furry.
d) The bones is stretched over the membrane.

2. a) In ancient times it was believed that sea monsters existed.
b) These monsters were called Kraken.
C) People had said that such monsters could swallow ten people and a ship.
d)Today we know no such thing as a sea monster that is there.

3. a)The mineral resources of the earth have been exploited.
b) They are uniformly distributed over the surface of the earth.
c)They are mixed with a large variety of impurities.
d)They are exhaustible resources.

4.a) The Stone Age was the marked time when humans is made weapons from stones.
b)Copper was first mineral learned to humans that probably mined.
c) Then humans made a more stronger durable mineral by mixing tin and copper.
d) The Iron Age was soon replaced by this age called the Bronze Age.

5.a) Rubber got its name because it could rub out pencil marks.
b) Rubber can bounce and Stretch.
c)All rubber used to come from tree earlier.
d) It is now made from oil or gas.

6.a) The largest bird in the world cannot fly at all.
b) Ostriches are so big that it is impossible for them to fly.
c) They can run as fast as racehorses.
d) They wander around in large flocks.

7.a) A shooting star flashes across the sky.