Once harm is _______ to the eco-system, all species will ________, including man himself. 

Interest is as_______to learning as the ability to understand,even more so.

Such a grammar mistake is _____ among the beginners of English study.5.      

Many people have donated that type of blood, but the blood bank needs ________.

 Only _____ people can have a good understanding of the lecture given by the scientist.