Questions

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

Ecology is the branch of science which deals with the study of Ecosystem (relation between the Organisms and their Environment.)

The United Nations General Assembly in November 2014 declared 15th July as World Youth Skills Day.

This day is celebrated all over the world to raise the awareness about the issue of unemployment among youth. 

Theme for the year 2017 is Skills for All.

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.

The First and Last Indian viceroys of India is C. Raj Gopalachari. 

Chakravarti Rajagopalachari, informally called Rajaji or C.R., was an Indian politician, independence activist, lawyer, writer, historian and statesman. Rajagopalachari was the last Governor-General of India, as India soon became a Republic in 1950.