Gymnosperms and angiosperms have flowers! ferns and bryophytes
immune system refers to any a ability of the body to resist Invasion by a disease causing organisms
For many of their illnesses scientist and doctors haven't treated them before so they don't know how to treat them or exactly if the animal can handle the treatment
Because their bodies tell them that they need more oxygen and so breathe faster, and try and get the oxygen their body requires and depends on.
The smallest prefix is deci
