Question

Seeds of certain plants fail to germinate if they do not pass through the digestive tract of fruit-eating birds. This is due to

Answer 1

it is due to the hard covering on seeds....
the seeds which have hard seed coat..can't germinate ....for their germination ..they have to pass through the digestive tract of fruit eating birds....
due to acid present in digestive tract ....the seed coat breaks....
leads to germination of seeds..

Answer 2

seeds of certain plants fail to germinate if they do not pass through the digestive tract of fruit-eating birds. This is due to

ANSWER:- Seed Coat Impermeability