Answer:
Maybe it is 5.50 because not much information is given to calculate it or to find it.
Double fertilization-plants with seeds (flowering plants), two male gametes joining with female gametophyte
Gametophyte generation-both (haploid, sexual stage stage-gametophyte, and the diploid stage that produces spores – sporophyte)
Endosperm formed-plants with seed because it is a tissue formed inside the seed which surrounds the embryo and provides nutrition
Mitosis-both (mitosis occurres in spores)
Spores develop into gametophytes-both but, in seedless plants sporophyte produces spores that will develop into a new organism (multicellular gametophyte) using mitosis, while spores of seed plants are produced internally and develop into more complex structures.
