The transition directly from a solid to a gas
Answer:
Pteridophytes are vascular plants but they do not produce flowers and seeds which mean their source of reproduction is unknown or hidden.
On the contrary, Spermatophytes as the name indicates, are seed bearing plants. They produced seeds and flowers. Examples are flowering plants, cactus, leather flower, buttercup and may more.
Explanation:
The answer is nitrogen fixation.
Hope this helps
