Reviewed 6 October 2026 · 4 min read
Test Guruji editorial · original lesson
Guest bookmark · this browser only, no account sync.
Separate the processes
Respiration releases usable energy from food; breathing is the physical movement of air. They are related but not synonyms. The body also needs nutrition, transport and removal of metabolic wastes.
In plants, xylem transports water and minerals, while phloem carries food products. In humans, arteries carry blood away from the heart and veins carry it towards the heart. This direction-based definition is safer than saying arteries always carry oxygen-rich blood.
Understand the exception
Pulmonary arteries carry blood from the heart to the lungs, where gas exchange occurs. They demonstrate why oxygen content cannot define an artery. Excretion removes metabolic waste; it is different from removing undigested food. Revise each system as input, process and output.
Sources and editorial context
Last editorial check: 6 October 2026. Verify changing facts and your exam’s requirements from current official notices. Practice questions are editorial originals.
Original revision quiz
Checking your account…