Omega-3 fatty acids are important because they
a. the body absorb calcium.
b. increase the stomach's ability to digest foods.
c. make the bones less brittle.
d. reduce the amount of hardened material that forms on artery walls.

Omega-3 fatty acids are important because they help reduce the amount of hardened material that forms on artery walls - d.

Omega-3 fatty acids are considered a good addition to any diet due to the fact how they affect cardiovascular health (in a positive way) as well as cognitive functioning. 

Idont understand what youre askimg