The answer to your question is D
The circulatory system takes the carbon dioxide from the cells to the lungs and the respiratory system expels ir.
Answer: a. Haploid spores are released to form zygotes, which grow into gametophytes.
A fern has two different stages of the life cycle; the sporophyte and gametophyte. In the sporophyte, spores are released. After this life cycle comes the gametophyte or the sexual phase, <span>haploid spores are released to form zygotes, which grow into gametophytes. </span>
I believe the correct answer is A.