Question

what happens when the two sperm cells travel down the angiosperm pollen tube? they both stimulate growth of the pollen tube. one fertilizes the egg, and the other combines with the two polar nuclei. one fertilizes the egg, and the other fertilizes the synergid. toward the micropyle. if one fails in fertilization, there is a backup nucleus.

Explanation:

In angiosperms, double - fertilization occurs. One sperm cell fertilizes the egg to form a zygote, and the other combines with the two polar nuclei to form the endosperm nucleus.

Answer:

one fertilizes the egg, and the other combines with the two polar nuclei.