Question

Cellulose-rich food substances are good source of roughage in
human beings because
(a) human beings do not have cellulose-digesting enzymes.
(b) cellulose gets absorbed in the human blood and converts
into fibres.
(c) the cellulose-digesting bacteria convert cellulose into
fibres.
(d) cellulose breaks down into smaller components which
are egested as roughage.


NCERT Class VIII
Science - Exemplar Problems

Chapter 2. Nutrition in Animals

Answer 1

d)  cellulose breaks down into smaller components which
are egested as roughage.

Answer 2

Answer:

a) Human beings don’t have cellulose digesting enzymes.

Explanation:

Roughage is fibre that cannot be digested by enzymes and adds to the digested food content and allows it to be passed through the gut. Cellulose is a component of the “cell wall”. Humans do not have cellulose and hence no enzymes like cellulose to digest it.  

Hence cellulose-rich foods cannot be digested but adds to the fibre content or bulk and acts as a good source of roughage helping digested food to pass through the gut.