Fill in the following blanks with suitable words:

(a) Alcohol is produced with the help of ............

(b)Blue-green algae fix................directly from air to enhance fertility of soil.

(c) Micro-organisms can be seen with help of a..........

(d) Cholera is caused by..............

(e) Common salt has been used to preserve............. and ............ for ages.

(f) The food material which is preserved by pasteurization is .................

(g) As a result of nitrogen cycle, the percentage of nitrogen in the atmosphere remains more or less…….