4th Dimension ~ At any/every moment in time we could be surrounded by 4th-dimensional beings and not see or detect them because we live in the 3rd-dimension. They could be observing/studying us and we wouldn’t know it.
Afterlife ~ We can die at any moment and no one knows if there's an afterlife. Nothing is guaranteed based on your faith or preference. Even if someone knew exactly what were to happen after death and supported it with evidence, no one would believe them therefore making it useless to even begin to talk about.
Cats and Dogs ~ Cats and Dogs such lovable creatures right? Well, if you were to die at home, your cat/dog would start licking you. That licking will turn to biting and then eating.
Zombie Outbreak ~ A zombie outbreak is technically possible. There have been cases of zombie ants and spiders. MedicalNewsToday says Ophiocordyceps is a type of fungi that has more than 200 species. Many species of fungi are dangerous (mostly since they are toxic to animals) but there is one thing that makes Ophiocordyceps scary beyond the others. This type can control insect behavior and feed on the body until it dies. In 2018, a zoologist from the University of British Columbia in Canada found that a unknown species of the Zatypota wasp can manipulate spiders' (Anelosimus eximius) behavior. This type of spider usually stays in packs. After being infected with the larva they began to stray away from their groups. When the larva gains full control it turns the spider into a zombie-like creature and spins a cocoon-like nest where it will become an adult. Before that happens it eats the spider. There is a possibility of a zombie outbreak taking place.
Author's Note: The sites I used for "Part 1" are:
Cats and Dogs