There is a difference in how reproduction occurs in gymnosperms compared to angiosperms: Only the sperm of angiosperms combine with two central cell nuclei to form a triploid endosperm.
a) The endosperm serves as the nutrient source for the developing embryo.
b) All of the other answer choices are incorrect
c) they are all characteristics common to both gymnosperms and angiosperms.
d) Both angiosperms and gymnosperms have pollen grains that form pollen tubes.