In seedless plants, haploid gametophytes are produced
a) diploid spores that undergo mitosis.
b) haploid spores that undergo meiosis.
c) diploid spores that undergo meiosis.
d) haploid spores that undergo mitosis.

The correct answer would be D) haploid spores that undergo mitosis.

Seedless plants such as ferns, horsetails, whisk ferns et cetera shows alternation of generation in their life-cycle that is, haploid gametophyte and diploid sporophyte phase.

Diploid sporophyte produces haploid spores with the help of meiosis.

These haploid spores divide with the help of mitosis to produce haploid gametophyte (male and female).

These gametophytes fertilize to produce a diploid zygote which divides and mature into a diploid sporophyte.  

Thus, haploid gametophytes are produced from haploid spores that undergo mitotic divisions.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands