<Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2013) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2013) (Learn how and when to remove this template message) </Td> </Tr> <Table> <Tr> <Td> </Td> <Td> This section needs expansion with: information about allergies not in the nose, e.g., skin reactions . You can help by adding to it . (March 2013) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs expansion with: information about allergies not in the nose, e.g., skin reactions . You can help by adding to it . (March 2013) </Td> </Tr>

How many cells are on a pollen grain