Which of the following regarding internal mammary artery is true? a) supply the heart
b) arise from the subclavian artery
c) arise from the aorta

The correct answer is option b) "arise from the subclavian artery" .

Explanation:

The internal mammary artery, nowadays known as the internal thoracic artery, is one of the most important arteries in the body, since it supplies the anterior chest wall and the breasts with oxygen. The internal mammary artery arise from the subclavian artery, particularly from its proximal part, and it extends up into the musculophrenic and the deep superior epigastric arteries.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.