Plants of this group are diploid and well adapted to extreme conditions. They grow bearing sporophylls in compact structures called cones. The group in reference is

• Monocots

• Dicots

• Pteridophytes

• Gymnosperms

Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.

Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a ferm; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.

Write a note on economic importance of algae and gymnosperms.

Both gymnosperms and angiosperms bear seeds, then why are they classified separately? 

What is heterospory? Briefly comment on its significance. Give two examples.

Explain briefly the following terms with suitable examples:
(i) protonema
(ii) antheridium
(iii) archegonium
(iv) diplontic
(v) sporophyll
(vi) isogamy

Differentiate between the following:
Red algae and brown algae

Differentiate between the following:
liverworts and moss

Differentiate between the following:
homosporous and heterosporous pteridophyte

Differentiate between the following:
syngamy and triple fusion