Question

Name the 15th group element that does not exhibit allotropy

Answer 1

Answer:

As: Yellow, Black and Gray (Grey); Sb: White, Yellow and Black. The same source suggests that Nitrogen has an allotrope named Dinitrogen while Bismuth has none. Chemwiki says:N2 does not have any allotropes.and doesn't comment on Bismuth.

Answer 2

Explanation:

self- pollination in flowers are: 1)dichogamy- the maturation of anthers and stigma at different time in a bi-sexual flower which prevents self pollination. 2) self- incompatibility : The pollen grains of a flower are not capable of completing growth on the stigma of the same flower.