Bacteria that feed off of food in the human gut and provide essential nutrients to their host are an example of
Commensalism
competition
mutualism
parasitism
predation

mutualism

Explanation:

They both are beneficial towards one another

mutualism

Explanation: both benefit, the bacteria feeds off host and the host gets nutrients

answer; /// i really don't understand your question/statement.but/lions do fight over territory and breeding rights, sometimes to the death,this is called( i hope this answered your luck

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.