The human lungs, heart, blood, and blood vessels work together to make up the cardiopulmonary
organ
organ system
tissue
cell

The answer to your question is Organ system

Because the earth is not round ,but it may seem round when viewed from ,our planet but true some points earth is not round was an oblate spheroid -a square that it squashed as globe however is not even a perfect oblate spheroid.in fact isaac newton's first proposed that earth was not perfectly round but it was an oblate spheroid instead.that mean a square that is squashed as its poles and swollen at the