Many discoveries in science have been accidental .This is true for plant hormones also .Can you jutify this stement by giving an example? Also what terms is used for such accidental finding

Suppose you are told that the linear size of everything in the universe has been doubled overnight. Can you test this statement by measuring sizes with a metre stick? Can you test it by using the fact that the speed of light is a universal constant and has not changed? What wll happen if all the clocks in the universe also start running at half the speed?

What types of forces are you familiar with ? Also give examples

What do you mean by the following also give example (a) Non-essemtial amino acids (b) Essential amino acids.

What is disease? How many types of diseases have you studied? Give examples.

(a) What is a slag ? (b) Give the principle of zone refining ? ( c) An ore sample of galena (PbS) is contaminated with zinc blende (ZnS) . Give an example of a chemical which can be used to concentrate galena selectively by froth flotation process. (d) What is meant by the term 'Pyrometallurgy' ?