I think it would be crocodile teeth
humans
The most common element in plant tissues is Carbon. This is why plants and animals are called carbon-based life forms; because we are made predominately out of carbon.
Some animals can hear higher frequencies than humans can. This is why animals can hear things like dog whistles, and we can't hear them. In all, animals can hear differently than humans in the way that they can hear more. Some animals can hear lower frequencies than humans can. Elephants can hear much lower frequencies than humans.
elephants
humans and animals
Cell with similar structure and functions are grouped into tissues.
There are many tissues that are similar, but for the most part there is no one tissue that is exactly the same between humans and even chimpanzees.
Most of animals are killed by humans
Animals are used because scientists want to spare humans. Most animals have similar genes to humans so animals give the same reaction humans would if the experiments were being tested on the humans. Using animals is a way to help keep the human population up and still be able to find cures for those everyday diseases.
rats and humans respond similarily to ingesting many medications/chemicals/etc, but pigs are the most physiologically similar to humans
msost animals are nasty that's how they are similar
humans are the most evil animals on this planet
Animals store only a small amount of energy in their body tissues because most is used for a life processes.
pigs have the most similar organs to humans.
Humans. Humans are animals and live in some of the most hostile habitats known.
Humans.
Enough of it can kill humans and animals, seeing as how it is a chemical, and most chemicals are harmful to humans and animals.