In angiosperms, two male gametes contained within a single male gametophyte participate in fertilization. One sperm nucleus combines with the egg to produce a diploid zygote, and the other sperm nucleus combines with two other haploid nuclei of the female gametophyte. This process is called
a. biparental inheritance
b. double fertilization
c. dihybrid crossing
d. single fertilization
e. multiple paternity