(a) The yeast cells fail to multiply in water but they multiply rapidly in sugar solution. Give one reason for it.
(b) Why does bread mould grow profusely on a moist slice of bread but not on a dry slice of bread?
(a) Since yeast is a non-green plant, it cannot make its own food. Thus, they don't get the energy to reproduce. However, in a sugar solution, it grows well, as sugar acts as a good source of energy.
(b) A moist slice of a bread provides all the favourable conditions needed by the spores of the bread mould to germinate. This is the reason why bread mould cannot grow profusely on a dry slice of a bread.