Question

answer the questions

Answer 1

1.the seeds become hallow because of containing air in it due to the exhaustion of its time 
2..q 1.they are very harmful for aquatic organisms and other animals .        2.it is harmful to us also it is mixed in water and some times it is added to the fruits and vegetables which we eat raw like apple , carrot etc
hope it will help you

Answer 2

1st answer is -- They float on water bcoz they are actually empty and lack the nutrients and other materials needs to propagate in plants.

2nd answer is -- Bcoz of the chemical stat on plant.

Hope this answer is true please comment and thanku