Hydrogen and hydroxide ions
Growth and development
Reproduction
Maintains homeostasis
Has cells
Metabolism
Heredity
Responds to stimuli
Adapts to environment
Carnivores, they eat other animals to obtain their food.
The heart is an organ (rather than a tissue) because it has an important (and complex) function. Tissues don't have nearly as many things in it as the heart does.
Hope this helps! :)