Question

foam accumulates on a the surface of dal kept for a long time in summer​

Answer 1

Answer:

Foam accumulates on the surface of 'dal' kept for a long time in summer due to trapping of water vapours in the saponins of dal. These foams also provide a good medium for microbial growth.

Answer 2

(1) dal is rich in proteins.

(2) During summer, bacteria attack the dal and cause fermentation resulting in the production of carbon dioxide gas.

(3) Therefore foam accumulates on the surface of the 'dal' kept for a long time in summer.