Breaking of glass is ___ change.

• Irreversible

• Natural

• Sudden

A desirable change is ____ as the change, which is beneficial or helpful to humans.

A desirable change could be brought about by nature or humans, physical or chemical in nature, could be occurring periodically or non-periodically, and could occur slowly or speedily.

• True

• False

1. A desirable change is generally carried out on purpose, mostly for the benefit of mankind.

Examples of Desirable Changes: curdling of milk and drying of clothes.

• This statement is true

• This statement is false

• Both

What does undesirable change cause?

• Undesirable changes lead to harmful and unwanted changes

• An undesirable change is generally carried out on purpose, mostly for the benefit of mankind

Examples of undesirable changes are -

• curdling of milk and drying of clothes.

• rusting of iron, rotting of fruits and vegetables, and spilling of milk.

When we see a ___ substance growing on a slice of bread, we immediately identify it as mould, and throw it away, because eating it is harmful for our health.

Who was alexander fleming?

• A shop wendor

• Cricketer

• an English microbiologist,

• Scientist

As of today, penicillin is a well-known ____. which is used to cure a number of infections caused by bacteria.

Alexander fleming saw something unusual while working in his laboratory in ..............

Complete the sentence

• May , 2025

• January, 1001

• April, 1999

• September, 1928.