Question

Heterosporous pteridophytes show certain characteristics, which are a precursor to the seed habit in the gymnosperms. One of such characteristics is
A. presence of vascular tissues
B. external water required for fertilization
C. presence of embryo stage
D. development of the embryo inside the female gametophyte

Answer 1

Hint: Plants in the Plantae kingdom have various phyla which have different unique features. Some have vascular systems, some are simple, some are complex, some generate seeds while some are seedless. The way from simple to complexity is all evolution which happens with the requirement and time.

Complete answer:
Heterosporous pteridophytes are the plants which make two types of spores-microspore and megaspore. There are two characters of the pteridophytes which will form as the precursor to the gymnosperms seed habit.
1. Retention of female gametophyte in the megasporangium on the plant body, to provide parental care to the embryo.
2. Development of zygote in the female gametophyte.
Let us learn about the options.
Option A. presence of vascular tissues: Vascular tissues are present in both groups. This does not have any link with the reproduction in the plants. They simply are the tract of food and water transport.
Option B. external water required for fertilization: There is a need for water in the fertilization in the gymnosperms. So this statement becomes incorrect.
Option C. presence of embryo stage: In the seed habit of gymnosperms, there is embryo but there are spores in the pteridophytes, which are naked. So this is incorrect.
Option D. Development of the embryo inside the female gametophyte: The development of zygotes and embryos takes place in the female gametophytes in pteridophytes which forms the precursor to the seed habit and thus evolution. The heterospory and retention of single megaspore within megasporangium give the female gametophyte, which will lead to seed habit.

So the answer is option D: development of the embryo inside the female gametophyte.

Note: Gymnosperms have no outer covering of the seeds. They do not give flowers and fruits. They are the non-flowering plants. Their strong root system is good for soil erosion. They are good sources of fuels like conifers. They are heterosporous and have two types of spores.