The answer to your question is bacteria
Unoxygenated blood from veins enters the right atrium then it goes down to the right ventricle then out through the pulmonary artery to the lungs where it becomes oxygenated blood which then enters the heart through the pulmonary veins and it goes to the left atrium and then is pumped down to the left ventricle and out through the aorta to the arteries where it travels to different organs and becomes deoxygenated and then the cycle repeats itself.
The lungs are considered to be an organ.
Animal cells don't have mitochondria and have smaller vacuoles than plant cells <span />
Answer: The main difference between lymphocytes and phagocytes is that lymphocytes generate specific immune responses against pathogens whereas phagocytes generate the same response to any pathogen. This means lymphocytes are the tools of the adaptive immunity whereas phagocytes are the tools of innate immunity
Explanation: