These lines are spoken by a captain who has been wounded in the war. He is relaying the information about Macbeth's brave fight against the enemy to King Duncan. He talks about how brave and valiant Macbeth was, so the audience can infer that he is a fierce warrior who will stop at nothing to ensure his win in a battle.
Plants are essential to the world, because plants take in carbon dioxide from humans and give out oxygen for us to inhale. This all happens through a process called photosynthesis.
