In angiosperms, zygote is diploid while primary endosperm cell is triploid. Explain.

Explanation

Zygote is the product of fusion of a haploid male gamete and a haploid female gamete, i.e. egg cell. Thus, it is diploid.
Male `underset("(n)") ("gamete") underset(+)(+) underset("(n)") ("Egg") underset(to) (to) underset("(2n)") ("Zygote")`
Whereas, primary endosperm cell is a product of fusion of secondary nucleus (2n) and a haploid male gamete so, it is triploid.
`underset("(2n)")("Secondary")` + Male `underset("(n)") ("gamete") to` Primary `underset("(3n)") ("endo)sperm cell