Botany and Plant Science

A male cone contains microsporophylls where male gametophytes ( pollen ) are produced and are later carried by wind to female gametophytes. The megaspore mother cell in the female cone divides by meiosis to produce four haploid megaspores; one of the megaspores divides to form the female gametophyte. So the correct option is 'Male and female gametophytes are independent of the sporophyte'.

Angiosperms and Gymnosperms resemble each other in many characteristics on of which is the presence of ovule. The difference lies in the appearance of ovule, in Angiosperm the ovule is enclosed in ovary, whereas in Gymnosperms the ovule is naked. 

Zoodiogamy is a type of fertilization in plants, wherein the male gametes or antherozoids swim in a film of water to the female gametes present in the archegonium. This type of plant reproduction relates to evolution and  is found in lower gymnosperms besides algae, bryophytes and pteridophytes.

Gymnosperms refers to the group of naked seed bearing vascular  plants. Their seeds are naked as these are not enclosed in an ovary, like that of the angiosperms. This group includes large trees, like the pines, conifers, cycads and Ginkgo. 

The "endosperm" is a tissue in which the nutrient substances necessary for the development of the embryo are deposited. In gymnosperms the endosperm is formed in the ovule during germination of the megaspore is a gametophytic tissue, which consequently becomes the female prothallus or the gametophyte with a haploid set of chromosomes. The archegonia in gymnosperms develop from certain cells of the endosperm.

In gymnosperms, below micropylar beak some of the cells of nucellus of ovule disintigerate to form pollen chamber.

In gymnosperms, the pollen chamber is a cavity formed in the nucellus of the ovule where pollen grains land and rest before germination.

Gymnosperms are wind-pollinated plants. They do not have to cover around seeds. They do not produce fruits or flowers. After pollination, they produce pollen tubes. This pollen tube carries the sperm cells to the egg. These eggs are located within the integument megasporangium. So, all these are the characteristics of gymnosperms.

The rachis and leaflet have diploxylic vascular bundles. At the region ofthe stem cortex, the leaf trace has only centrifugal xylem, hence, it is endarch. These traces enter the leaf as the rachis separates, the centripetal xylem appears and it is in the exarch condition. The leaflet has a single midrib bundle and is in the diploxylic condition.

Both gymnosperms and angiosperms are seed-bearing vascular plants. Gymnosperms are the seed bearing plants wherein seeds are naked i.e. not enclosed by ovary or fruit. Angiosperms are seed bearing plants wherein seeds are enclosed within ovary or fruit. Both have a well-differentiated stem, root and leaves. Thus, the correct answer is option B.

Endosperm in gymnosperms is formed before fertilization and is always haploid.

Bordered pits xylem tracheids are common in gymnosperms.

Vessels are limited in growth, are joined end to end to form continuous tubular structures with perforations in their cross walls. Water and minerals are efficiently conducted through these perforations. Vessels are present in most of the angiosperms. Tracheids are elongated and non-perforated. They have only pit pairs, at the regions of union with other tracheids. Conduction of water and minerals is not as efficient as in vessels. Tracheids are found in most of the gymnosperms.
Thus, the correct answer is option A.

In gymnosperms, the endosperm is formed before fertilization from the female gametophyte, making it haploid. In angiosperms, it is formed after fertilization via triple fusion, making it triploid.