Oxygen supply to human brain

The arteriograph shows arteries carrying oxygen-rich blood to the brain. The arrangement of the arteries allows blood to be supplied by another route if one of the pathways is blocked. ('The Human Brain Book' by Rita Carter)

Bastinando punishment in Persia in the 1800's

 (Source:'The Graphic', May 16,1896 - an English Newspaper)

Region with the fastest growing population in the world

No region of the world is growing faster than sub-Saharan Africa. Today's population of 926 million may hit 2.2 billion by 2050. (National Geographic, July 2014)

Momentum

The boulder, unfortunately has more
momentum than the runner

Momentum is the mass of an object multiplied by its velocity. The momentum of an object depends on its mass and velocity. This means that an object's momentum changes as it accelerates. Momentum can be transferred between objects. When a moving ball collides with a stationary one, for example, the first ball transfers some of its momentum to the second ball. The total momentum of the two balls is the same as the first ball's momentum before the collision. This is called the principle of conservation of momentum. 

(Dictionary of Science, by Neil Ardley)