Giving relevant examples, explain how seeds and fruits are adapted to the various methods of dispersal (20 marks)

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  • During the day, air diffuses into large air spaces of the spongy mesophyll; through the stomata; 
  • The carbon (IV) oxide in the air diffuses into photosynthetic cells; in solution form; 
  • During photosynthesis, carbon (IV) oxide is used up; while oxygen is released; some of the oxygen is used in respiration; while the rest diffuses out of the leaf; through the stomata;
  • During the night, air diffuses into the air spaces; through the stomata, the air dissolves into the film of moisture; oxygen in the air diffuses into the cells; and is used for respiration; 
  • Carbon (IV) oxide produced; diffuses out through stomata; due to a concentration gradient diffusion gradient; 
  • At night, carbon (IV) oxide accumulates in the leaf since photosynthesis does not occur; 
  • Some gaseous exchange also takes place through the cuticle, and through the epidermis of young leaves, roots and stems; 
  • Some plants exchange gases through breathing roots pneumatophores; 
  • Older stems exchange gases through lenticels;

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