Actually, yes they do. They are not hard like those of an apple or orange but if you slice a banana lengthwise you will see small soft seeds running the length of the fruit. The little black dots you see running along the core are seeds.
No, spiders cannot even eat them! They cannot chew food. When they get to the bug in their web, they bite it and inject venom. The venom either paralyzes or kills the bug. Then the venom turns the...