Question

Give scientific reasons for the following:
(a) In colder parts of the world, summer vegetables are sun dried.
(b) Atta (wheat flour) can be stored for a longer duration than cooked chapattis.
(c) When yeast is kneaded with dough, dough rises after some time.
(d) Shoes and clothes get mould easily during the rainy season.

Answer 1

(a) In colder parts of the world, summer vegetables are sun dried and preserved for the winters​ because it is not possible to grow fresh food in the winter season.

(b) Cooked chapattis contains moisture; therefore, they provide favourable conditions for the growth of microorganisms that spoil them. However, atta (wheat flour) can be stored for a longer duration as it does not have moisture in it.

(c) When yeast is kneaded with dough, the carbon dioxide released during the respiration of yeast causes fermentation and makes the dough to rise.

(d) Shoes and clothes get mould easily during the rainy season because mould grows best when there is warmth and enough moisture.