Which of the following statements about ferns is not true?
(a) ferns have motile sperm cells that swim through water to the egg-containing archegonium (b) ferns are vascular plants
(c) ferns are the most economically important group of bryophytes (d) the fern sporophyte consists of a rhizome, roots, and fronds
(e) the diversity of ferns is greatest in the tropics