The climate? That would fit I suppose.
Answer: 1, 3, 5
new nuclei begin to form
chromatids arrive at opposite ends of the cell
cytoplasm divides and two daughter cells are formed
One sperm fertilizes the egg cell forming a diploid zygote, the other sperm fuses with the two polar nuclei forming a triploid cell that develops into endosperm
Mesozoic, the era contained both large reptiles and small birds/mammals. It's interesting, coming from an evolutionary biology.
Hope this helped!