They need to adapt because it helps them be safe from predators and get food.
Some animals live in packs or groups (wolves, ants, meerkats) and they depend on each other for survival, some even have specific jobs. Some hunt while other protect the home and some are used just...
they eat it
Yes, small plants can feed off the log. That is their roots can feed off the logs and help break down the log.
The welfare for animals help out the animals by providing nutrition, and shelter from the elements. They also provide veterinary care for the animals.