after the pollen tube
Chapter 26 1 Figure 26.8 B. The diploid zygote forms after the pollen tube has finished forming, so that the male generative nuclei can fuse with the female gametophyte. 3 D 5 C 7 A 9 B 11 C 13 B 15 C 17 D 19 Both pollination and herbivory contributed to diversity, with plants needing to attract some insects and repel others. 21 The trees are adapted to arid weather, and do not lose as much water due to transpiration as non-conifers. 23 The resemblance between cycads and palm trees is only superficial. Cycads are gymnosperms and do not bear flowers or fruit. Cycads produce cones: large, female cones that produce naked seeds, and smaller male cones on separate plants. Palms do not. 25 Using animal pollinators promotes cross-pollination and increases genetic diversity. The odds that the pollen will reach another flower are greatly increased compared with the randomness of wind pollination.