"Anything that triggers an immune response" is the definition of which immune system term?
a macrophage
an antigen
an antibody
a cytokine

i would have a lunch. it's one big package of food, making it one food. : p

feral cats are estimated to eat tens of millions of native animals each night in australia

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.