There's no any exact scientific results and nobody currently know what will exactly happen, but some scientists suggested that the sun might expand and dies that leads to the end of the world but some says there will be a new sun being born and like that.
Answer: They Reproduce and have Genetic Material
You could talk about how plants supply food for animals.
E.g cacti provide food and water for desert animals and rodents.
small rodents provide food for larger animals and snakes.
some animals will clean larger animals in a mutualistic relationship.
