4-ASTEROIDS and METEORITES-

Many different types of Asteroids present near and far from the earth are in regular motions. Some are revolving round the earth continuously. Some small ones are colliding daily to our earth surface but are not making much damage to it. Some of the bigger ones are believed to collide the earth in the near future which can make much destruction. This is also caused by the changes made in nature day by day and also due to change in magnetic conditions which results in change in gravitation conditions also.
The end of the dinosaurs present few thousands of years back on this earth were also believed, due to the collisions of some asteroids then.
(Note that an asteroid just 15 km wide is said to have destroyed the dinosaurs)
So think of the human race, what affect can these asteroids, have on us and also on other living beings on these earth.