Cats, dogs, chickens
Surprisengly, the most deadliest animal is a hippo! People who come close to one can get trampled over and killed! and as for the plant, that is the castor oil plant. one seed could kill a 160 kg man
when the animal (pig,duck,sheep etc.)is big enough to eat they kill it so they can eat it,most of the time that's why people have them in a farm, they also kill it for animal abuse or they are little and don't have the opportunity to eat or do something so they kill it example: when a horse is in a race competition and he hurts one of it's legs it dosen't have any cure so they just kill it
they are not the most dangerous. Although they only eat plants they can kill a person with there teeth. They would not eat a person but they would kill one but they aren't the most dangerous.
The African Black Mamba. With just one bite the venom is so powerful it could kill up to 200 people! It is always fatal if not treated immediately.
lions will kill and eat a hyena
Just as simple as killing one of the most precious and rare animal. And it makes more and more animal's lose their liver and preferred enviorment everyday.
Elephants, they walk slow, but can kill you with one stomp.
Food.
one of the good points is you gain food from the animal that you kill. :(
carbon monoxide is one poisonous gas that can kill a human or animal. it is found in households, but it might not be the chemical/gas you are looking for. there are many potential chemical killers in the common house, but this is the most notorious.
Depending on the size of the animal. Then yes it can with a good head shot. If the animal is too big it may not kill it, and then you have one very mad animal at you.
abandonment is the biggest that animals die from. shooting is another way animals die because people think it is fun to abuse animals. and lastly suffocation it is another big one. The Biggest thing that will kill an animal is abuse and malnourishment. people think that it is ok to abuse and starve an animal because they think that they have no feelings. suffocation and drowning are the next 2 and torture is the third.