Answers

  • Brainly User
2014-08-05T18:57:21+05:30
It is because of the outer coverings.the outer one is called as exine,which is made up of sporopollenin and the inner one is known as intine made up of cellulose and pectin.
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2014-08-09T09:16:30+05:30
Mineral contituenstas present in them
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