Postal or Sorting Assistants Model Paper 3 With Solutions

(a) Lichens are the best indicators of air pollution. Theyare widely used as environmental indicators or bioindicators. If air is very badly polluted with sulphur dioxide lichens would not grow but green algae may be found. If the air is clean, their shrubby, hairy andPractice Set-6leafy lichens become abundant. Lichens are thus commonly seen on hilly areas but not polluted cities.