Falling leaves contain a lot of useful substances.
A heap of green leaves is lying in one corner of a park. The green leaves in the heap burn with difficulty because :
(a) they contain a tough material called cellulose
(b) they contain a lot of water
(c) they contain a green pigment chlorophyll
(d) they do not get sufficient oxygen for burning
Question 20 The substance that triggers the fall of mature leaves and fruits from plants is (a) auxin (b) gibberellin (c) abscisic acid (d) cytokinin
Which method will you use to separate the substances in each of the following mixtures?
(a) water + alum
(b) camphor + sand
(c) water + soil
(d) tea + tea leaves.