Considering how the body is orginized, give one reason why it is so difficult for scientists to build a heart

There is no guarantee that a human's body will accept the heart even if scientists try to build it.

Explanation:

The heart is a muscular organ that pumps blood through arteries and veins.  Human hearts are different from any other creature's hearts. There is the absence of a source for cells and tissues. It is very difficult for scientists to build a heart. There is no guarantee that a human's body will accept the heart even if scientists try to build it.

answer///weigh training and pilates;

true. these things define the personality of the person.