Questions

Breaking of relationships is prevented once referential integrity on a database is enforced

Heritable variation is one of the four most important factors that affect whether natural selection can occur. These factors include

1) Heritable variation

2) Descent with modification

3) Struggle for survival, and necessarily if the others are satisfied

4) Survival of the fittest.

Heritable variation allows for possibly beneficial, negative, or even neutral mutations to get filtered during each generation by natural selection--weeding out negative mutations, passing on positive and neutral ones. Without heritable variation, species would quickly fall victim to parasites who take advantage of identical genetic material in a population and evolution would not occur.

Variation is the raw material of evolution.

Because arteries have to have thick walls for use of protection. Its when you get to veins where the walls get thinner. And the use of the heart is to pump blood to all of the cells and organs in the body so it would be to transport blood away from the heart.

i.e. 

Arteries = Away from the Heart 
Veins = Back to the Heart.

This question can be answered in several ways. You can describe your education: fine arts with fashion/design focus. You can describe your work experience: fashion houses, employers, employees, and of course your actual work (the portfolio). Or you can describe your personal characteristics.

A Secret is what you want to share if you have with you. And if you share that secret with anyone, then secret will not be with you only.