Question

In fern sex organ are found on
A. Protonema
B. Prothallus
C. Sporophyte
D. Sporophyll

Answer 1

Hint:- A fern is a member of a group of vascular plants which have neither seeds nor flowers and reproduce through spores. By being vascular, i.e., having specialised tissues that conduct water and nutrients, and having life cycles in which the dominant phase is the sporophyte, they differ from mosses.

Complete Answer:- The leafy "branches," consisting of leaflets called pinnae, are the fronds. There are spots containing spores on the underside of some pine nuts. Not all pines and fronds have spores. Fertile fronds are called fronds which do have them. Spores are tiny structures containing the genetic material necessary for a new fern to grow. It may be green , yellow, red, brown, orange, or black. In structures called sporangia, which often clump together to form a sorus, spores are encased.
Sporangia are covered by membranes called indusia in some ferns. The sporangia are exposed to air in other ferns. The same gametophyte can produce sperm and eggs, so a fern can self-fertilize. The benefits of self-fertilization are that less spores are lost, no external gamete carrier is needed and their characteristics can be preserved by organisms adapted to their environment. The benefit of cross-fertilization, when it occurs, is that it is possible to introduce new traits into the species.The antheridium (male organ) is located on the lower surface of the fern prothallus and the archegonium (female organ) is located on the upper surface of the fern prothallus.

So, the correct option is (b) prothallus

Note:- A haploid spore grows into a haploid gametophyte during sexual reproduction. The gametophyte is fertilised and grows into a diploid sporophyte if there is enough moisture. Spores are formed by the sporophyte, completing the life cycle. Asexual reproductive strategies include apogamy, polyferous frond tips and propagation of rhizomes