Heteromorphic seeds of Asteraceae and Chenopodiaceae don't permit . . . . . . . . exchange.

Solution (By Examveda Team)

Heteromorphic seeds of Asteraceae and Chenopodiaceae don’t permit gaseous exchange.
Heteromorphic seeds usually differ in colour, size and shape as well as in dispersal, dormancy, and germination. It may be considered an adaptation to maximize the fitness of plants under harsh and unpredictable environments.