What is heterospory?

1 What is the basis of classification of Algae? 2 Write a note on economic importance of algae. 4 Explain briefly the following terms with suitable examples:-(i) protonema(ii) Antheridium(iii) Archegonium(iv) Diplontic(v) Sporophyll(vi) Isogamy 5 Write the difference between the liverworts and moss.