Erythropoiesis (from Greek 'erythro' meaning red and 'poiesis' meaning to make) is the process which produces red blood cells (erythrocytes).
Birds and mammals have the following characteristics in common: they are vertebrates, meaning they have an internal skeletonthey are warm-bloodedthey breathe using lungs, so â¦ have full respiratory systems they have circulatory systems. Most mammals give live birth, but there is a sub-group known as monotremes, which are the egg-laying mammals. 2  This group includes just the platypus and the echidna. 3  They are still mammals because, like all mammals, they feed their young on mothers' milk.
Best Answer: They are all warm-blooded, and they all have hair even if you can't see it (including dolphins and whales). Mammals all share mammary glands (milk producing glands). This is the biggest feature, also mammals use 3 bones for hearing and they have hair. Should be noted that endothermy (warm-blooded) is not unique to mammals, birds also share this characteristic.