Question

Some seeds like soap nuts have very hard shells. Why it is so?

Answer 1

some seeds like soapnuts have very hard shell. Because when seeds are in unfavourable conditions or adverse atmospheric conditions the shell or seed coat protect the seed from such a condition.
If the seeds come and contact with water and necessary nutrient soil they germinate.

Answer 2

Answer:

1) some seeds like soap nuts have very hard shell.

2) because when seeds are in unfavourable or adverse atmosphere conditions the shell or seed coat protects the seed from such a contact .

3) If the seeds come in contact with water and necessary nutrients some germinate .